Hate to be that guy but the fishing line still doesn't quite line up when using First-Person Model. It's way better than Tide 1.5 but still not right.

Tide 1.6 with any version of First-Person Model:

Latest version of First-Person Model on it's own:

First-Person Model version 2.4.3 on it's own:

It's worth mentioning that the vanilla fishing line doesn't even line up on the latest version of First-Person Model but it does in version 2.4.3.
However with Tide 1.6 it doesn't line up no matter what version I use.

This happens on 1.20.1 and 1.21.1

Interesting. I assumed switching to the third person render view would fix this, but it appears that it doesn't.
Looking at the code for First-Person Model, this may be something that you would want to ask the First-Person Model dev about. I don't know if there's much else I can do here.

Interesting. I assumed switching to the third person render view would fix this, but it appears that it doesn't. Looking at the code for First-Person Model, this may be something that you would want to ask the First-Person Model dev about. I don't know if there's much else I can do here.

Any update on this? If you want, I could try to get in contact with the dev.

I let the dev know and they said this:
tr7zw/FirstPersonModel#547 (comment)

Huh, looks like there is indeed a bug that the player offset isn't applied anymore. I might take this as chance to fix this entire mess in the first place, trying to correctly like the line to the fishing rod via NEA.