So every time I put a *.schem folder in the schematics folder and go ingame they don't show anyone know about this issue?

I'm running fabric 1.17,1
btw

Those schematics are in the Sponge schematic format, which is for example used by World Edit in 1.13+. Currently only the 1.12.2 version of Litematica can directly use that format. Support for that schematic format will come to the 1.13.2+ versions of Litematica with the next update from 1.12.2, but that is still some time away.

So for now to use those, you would have to paste them to a temporary world with World Edit, and then save them from that with Litematica. Here is a quick howto on doing the pasting, if you are not familiar with World Edit: #265