Greetings,
I experimented with the pack a bit and found a small optimization opportunity with flat like blocks such as ladders, vines, sculk veins and glow lichens. For each of them, you can enable face culling for the face that faces the wall if one is present. You are able to see the difference if you look out for it, but it shouldn't be noticeable in normal gameplay.

Here is a proof of concept for vines and ladders for you to take a look at:
ladder.json
vine.json

Unfortunately, I wasn't able to get this working for sculk veins and glow lichens. Note that, disabling shading for glow lichens might also improve performance a tiny bit.

Thank you for your feedback.
I have considered this option before, but found that the back of the ladder and vines can be seen from the side, which may help players find thin blocks that are not facing towards them.
I will fix the issue of inconsistent texture orientation between Resin Clumps, Sculk Veins, and Glow Lichen in the next version and cull their backside.

Disabling block shadows does not significantly improve performance. Simply No Shading is a good example.

This improvement could be made for sculk veins and glow lichens. There is only a 0.1 spacing to the block behind them compared to 0.8 for laddders and vines. You can barely see the face even if you try.

I just mentioned the shading due to the option being used in the default vines.