Thanks for your post! Does every snap command freezes? Can you please try to run: snap version and snap changes ? The output of those two (if they work) would be very helpful.
There is also SNAPD_DEBUG=1 snap version (or any other command) that might be helpful. Snapd itself should do some logging. So the output of journalctl -u snapd would be great.
Strace is great of course, however when using it with go programs some extra options are required or it hangs. Jamie did a great write-up on this: Stracing snap commands - the important part are the -e !select, ... bits.
Please let us know if you find anything and if you can get the logs from above (snap version,changes, journalctl) that would be great.