There is a few Wall mods on the page.
But i miss bigger and stronger walls, but i feel that just scaling up the vanilla wall will lose the flexibility of 1x1 space.
Merging Walls may be a thing?

Yes, it seems very similar to merging chests but I won't be implementing that mod. If you want you can use codebase of merging chests to create merging walls mod. I can only see one possible problem: connecting to other nearby wall segments but I'm sure it can be worked around.

Thx.
Im thinking of using Rails as walls, fast to place, connects well and are a bit bigger (2x2)
Merging or Rails, one should work.