I suspect (but not sure) that snapd uses temporary space for persistence. This is what findmnt tells me:
TARGET - SOURCE - FSTYPE
/snap - /dev/sdb[/snap] - ext4
/snap/snapd/12398 - snapfuse - fuse.snapfuse
/snap/core18/2074 - snapfuse - fuse.snapfuse
Should I try to move it to actual disk space and mount from there using C: and D: drives:
/mnt/c - C:\ - 9p
/mnt/d - D:\ - 9p
Not sure if it will work as the example I found is not for WSL:Move snap packages to another location/directory