17 days ago my pull request with three nice structure block additions for Carpet was merged. One of the options I added there was structureBlockLimit, and unfortunately, after it was released in the latest Carpet Mod version, Andrew54757 noticed it crashes with Tweakeroo.
More specifically Tweakeroo's TWEAK_STRUCTURE_BLOCK_LIMIT uses a mixin to change the limits of the structure blocks using @ModifyConstants and I did exactly the same thing for carpet's structureBlockLimit. My solution to that problem was a bit better though because I also got rid of the 256 upper limit and obviously made it work on dedicated servers (according to the description of 70af173, on Tweakeroo it only works in singleplayer).
I wanted to try the Tweakeroo's solution in-game but it didn't work for me, not sure if I did everything right.

This was already fixed in the 2021-02-04 build of Tweakeroo. (On my server there are even a few builds after that already.)

Is it a temporary fix or a proper solution? Should I just close this issue?

What constitutes a temporary fix vs. proper solution? I changed the @Override into an @Inject. So it does not crash with Carpet anymore, but both mods can co-exist now.

Again, I can't get Tweakeroo's limit change to work. It always brings the values back to 46 even if the tweak is enabled and set to 256.

Oh hah true, the tweak wasn't actually working, because my @ModifyConstant was still using the old value of 32. I fixed that too now.

Since this issue is fixed in the latest version, can someone close this issue?