fixing problem 1:
get_debug_state tries to serialize non buffer fields/keys (1 indent missing)
edit: after further testing this change can be tricky.
DebugLinkState may contain some other filed types not only bytes (like int for example) but in the same time they might be complex and not serializable.
see thp state:

<DebugLinkState: {'mnemonic_secret': b'all all all all all all all all all all all all', 'passphrase_protection': False, 'reset_entropy': b'', 'mnemonic_type': <BackupType.Bip39: 0>, 'tokens': ['{', '"component"', ': ', '"SimplePage"', ', ', '"active_page"', ': ', '0', ', ', '"page_count"', ': ', '2', ', ', '"content"', ': ', '{', '"component"', ': ', '"AddressDetails"', ', ', '"qr_code"', ': ', '{', '"component"', ': ', '"Frame"', ', ', '"title"', ': ', '{', '"component"', ': ', '"Label"', ', ', '"text"', ': ', '"Scan QR code to pair"', '}', ', ', '"content"', ': ', '{', '"component"', ': ', '"Qr"', ', ', '"text"', ': ', '""', '}', ', ', '"button"', ': ', '{', '"component"', ': ', '"Button"', ', ', '"icon"', ': ', 'true', '}', '}', '}', '}'], 'thp_pairing_code_entry_code': 417041}>

fixing problem 2:
UI client assumes that dataObject.response is a string but in case of debug state it is an object

example: send JSON to server

{"type": "emulator-get-debug-state"}