[BUG] 3rd Person Player Model Has a Seizure Upon Loading Previously Existing Save

[resetium]

Before reporting, make sure your problem isn't caused by the game running out of RAM and you have read the installation guide carefully.
If the game crashes to your desktop without showing a crash screen it's a RAM issue. Don't submit this kind of issue. Please view the installation guide for how to solve this issue.
If this is not the case check the checkbox below by replacing the space between brackets with an 'x'.

• Yes, I'm sure this problem isn't because my game ran out of RAM.

^ 16gb allocated, I have 32 available

Describe the bug
Upon loading the game for the third time (first crashed because of passableleavescore, second worked), my player model has decided that it is completely broken from the waist up.

Bit hard to understand given this image, but my torso is spinning at insane speeds (along the x axis, anchored at the legs, where forward is positive z), while my arms seem to be doing the same (anchored at the shoulders, spinning along the z and x axes).
I... don't even know what happened.
I should also bring up that this seems to be causing IMMENSE lag.

To Reproduce
I'm not sure, as I don't even know what mod makes this model.

Expected behavior
It worked fine when I loaded my save the first time.

Details
Please fill out the blanks below:
Modpack Version: ( 1.35.2 )
Did you add or remove mods? ( No )
Did you edit any config or script? ( No )
Using shaders? [Write 'Default' if you are using default shader, if you are not using the default shader please write the name of the shader you are using.] ( Internal )
Singleplayer, LAN game or server pack? ( Singleplayer )

Additional context
What mod even does this?

[resetium]

Note: For... whatever... reason, not only does my avatar completely disappear when I start walking, if I walk in certain directions I gain speed 5.
...So anyway, if you need any extra info like a log or something, just ask and I'll upload it.

[anabsolutesloth]

Check your BetterFPS mod settings, ensure it is not on Taylor's Algorithm.

[resetium]

It was, apparently.
I don't know how something like that is possible, to be honest, but computers make less sense the more you learn to program them anyway. Regardless, thank you!
I'll close this once I have the settings right and things aren't breaking.