Use the JoinRuleSettings component for the guest link access prompt.

res/css/views/settings/_JoinRuleSettings.pcss

@@ -53,6 +53,14 @@ Please see LICENSE files in the repository root for full details.
         display: block;
     }
 
+    &.mx_StyledRadioButton_disabled {
+        opacity: 0.5;
+    }
+
+    &.mx_StyledRadioButton_disabled + span {
+        opacity: 0.5;
+    }
+
     & + span {
         display: inline-block;
         margin-left: 34px;

src/components/views/rooms/RoomHeader/CallGuestLinkButton.tsx

@@ -14,10 +14,10 @@ import { EventType, JoinRule, Room } from "matrix-js-sdk/src/matrix";
 import Modal from "../../../../Modal";
 import ShareDialog from "../../dialogs/ShareDialog";
 import { _t } from "../../../../languageHandler";
-import SettingsStore from "../../../../settings/SettingsStore";
 import { calculateRoomVia } from "../../../../utils/permalinks/Permalinks";
 import BaseDialog from "../../dialogs/BaseDialog";
 import { useGuestAccessInformation } from "../../../../hooks/room/useGuestAccessInformation";
+import JoinRuleSettings from "../../settings/JoinRuleSettings";
 
 /**
  * Display a button to open a dialog to share a link to the call using a element call guest spa url (`element_call:guest_spa_url` in the EW config).
@@ -99,7 +99,6 @@ export const JoinRuleDialog: React.FC<{
     room: Room;
     canInvite: boolean;
 }> = ({ onFinished, room, canInvite }) => {
-    const askToJoinEnabled = SettingsStore.getValue("feature_ask_to_join");
     const [isUpdating, setIsUpdating] = React.useState<undefined | JoinRule>(undefined);
     const changeJoinRule = useCallback(
         async (newRule: JoinRule) => {
@@ -120,27 +119,22 @@ export const JoinRuleDialog: React.FC<{
     );
     return (
         <BaseDialog title={_t("update_room_access_modal|title")} onFinished={onFinished} className="mx_JoinRuleDialog">
-            <p>{_t("update_room_access_modal|description")}</p>
-            <div className="mx_JoinRuleDialogButtons">
-                {askToJoinEnabled && canInvite && (
-                    <Button
-                        kind="secondary"
-                        className="mx_Dialog_nonDialogButton"
-                        disabled={isUpdating === JoinRule.Knock}
-                        onClick={() => changeJoinRule(JoinRule.Knock)}
-                    >
-                        {_t("action|ask_to_join")}
-                    </Button>
-                )}
-                <Button
-                    className="mx_Dialog_nonDialogButton"
-                    kind="destructive"
-                    disabled={isUpdating === JoinRule.Public}
-                    onClick={() => changeJoinRule(JoinRule.Public)}
-                >
-                    {_t("common|public")}
-                </Button>
-            </div>
+            <p>{_t("update_room_access_modal|description", {}, { b: (sub) => <strong>{sub}</strong> })}</p>
+            <p>
+                {_t("update_room_access_modal|revert_access_description", {}, { b: (sub) => <strong>{sub}</strong> })}
+            </p>
+            <JoinRuleSettings
+                room={room}
+                disabledOptions={new Set([JoinRule.Invite, JoinRule.Private, JoinRule.Restricted])}
+                beforeChange={async (newRule) => {
+                    await changeJoinRule(newRule).catch(() => {
+                        return false;
+                    });
+                    return true;
+                }}
+                closeSettingsFn={() => {}}
+                onError={(error: unknown) => logger.error("Could not generate change access level:", error)}
+            />
             <p>{_t("update_room_access_modal|dont_change_description")}</p>
             <div className="mx_JoinRuleDialogButtons">
                 <Button

src/components/views/settings/JoinRuleSettings.tsx

@@ -36,6 +36,7 @@ export interface JoinRuleSettingsProps {
     onError(error: unknown): void;
     beforeChange?(joinRule: JoinRule): Promise<boolean>; // if returns false then aborts the change
     aliasWarning?: ReactNode;
+    disabledOptions?: Set<JoinRule>;
 }
 
 const JoinRuleSettings: React.FC<JoinRuleSettingsProps> = ({
@@ -45,6 +46,7 @@ const JoinRuleSettings: React.FC<JoinRuleSettingsProps> = ({
     onError,
     beforeChange,
     closeSettingsFn,
+    disabledOptions,
 }) => {
     const cli = room.client;
 
@@ -147,7 +149,7 @@ const JoinRuleSettings: React.FC<JoinRuleSettingsProps> = ({
                     }
                 });
 
-                closeSettingsFn();
+                closeSettingsFn?.();
 
                 // switch to the new room in the background
                 dis.dispatch<ViewRoomPayload>({
@@ -397,7 +399,7 @@ const JoinRuleSettings: React.FC<JoinRuleSettingsProps> = ({
             name="joinRule"
             value={joinRule}
             onChange={onChange}
-            definitions={definitions}
+            definitions={definitions.map((d) => (disabledOptions?.has(d.value) ? { ...d, disabled: true } : d))}
             disabled={disabled}
             className="mx_JoinRuleSettings_radioButton"
         />

src/i18n/strings/de_DE.json

@@ -3693,8 +3693,11 @@
         "unavailable": "Nicht verfügbar"
     },
     "update_room_access_modal": {
-        "no_change": "Ich möchte die Zugriffsebene nicht ändern.",
-        "title": "Ändern Sie die Zugriffsebene des Raums"
+        "description": "Um einen Konferenzlink zu erstellen müssen sie es Gästen erlauben diesem Raum beizutreten ohne deren matrix id einzuladen. Der Raum muss <b>Öffentlich</b> sein oder sie mussen es den nutzern erlauben <b>Beitrittsanfragen</b> zu stellen.",
+        "dont_change_description": "Wenn sie die Raum Zutrittseinstellung nicht ändern möchten, kann ein neuer Raum fuer die Konferenz erstellt werden.",
+        "revert_access_description": "(In den Raum Einstellungen kann die Zutrittseinstellung zurückgesetzt werden: <b>Sicherheit</b> / <b>Zutritt</b>)",
+        "no_change": "Ich möchte die Raum Zutrittseinstellung nicht ändern.",
+        "title": "Ändern Sie die Raum Zutrittseinstellung"
     },
     "upload_failed_generic": "Die Datei „%(fileName)s“ konnte nicht hochgeladen werden.",
     "upload_failed_size": "Die Datei „%(fileName)s“ überschreitet das Hochladelimit deines Heim-Servers",

src/i18n/strings/en_EN.json

@@ -3718,9 +3718,10 @@
         "unavailable": "Unavailable"
     },
     "update_room_access_modal": {
-        "description": "To create a share link, you need to allow guests to join this room. This may make the room less secure. When you're done with the call, you can make the room private again.",
-        "dont_change_description": "Alternatively, you can hold the call in a separate room.",
+        "description": "To create a share link, you need to allow guests to join this room without inviting there user id. The room needs to be <b>public</b> or you need to allow users to <b>ask to join</b>.",
+        "dont_change_description": "If you don't want to change the access of this room, you can create a new room for the element call.",
         "no_change": "I don't want to change the access level.",
+        "revert_access_description": "(This can be reverted to the previous value in the Room Settings: <b>Security & Privacy</b> / <b>Access</b>)",
         "title": "Change the room access level"
     },
     "upload_failed_generic": "The file '%(fileName)s' failed to upload.",