I've been trying the COSMIC store and it looks like it killed my apt somehow. Apt says that there is a version mismatch between some libc6 packages, but I checked with dpkg and it all looks correct.
Apt says that I've a newer version of some packages but that is not true. Is there any way to fix this?
EDIT: Fixed formatting
Okay, I've read into your post a bit more and something is fishy. You have libc6 for different CPU-architectures installed.
Programs for i368 and amd64 should not be installed on the same machine. The error probably stems from that.
Run the following to find out the architecture:
uname -p
If it says 'x86_64' then it's amd64 and if it's something like 'i368’ then it's that. Otherwise, your system might be really borked...
And then remove the wrong one.