@veritanuda you have copied the contents of snap files to another disk. Not the snaps themselves. This won’t end well.
The disk space consumed by snaps is all in /var/lib/snapd/snaps, not /snaps
alan@hal:~$ du -hs /var/lib/snapd/snaps
When you ‘snap install’ something, you get a .snap file in /var/lib/snapd/snaps/ - e.g. for teleconsole I have
alan@hal:~$ ls -l /var/lib/snapd/snaps/teleconsole_3.snap
-rw-r--r-- 1 root root 3661824 Oct 3 04:04 /var/lib/snapd/snaps/teleconsole_3.snap
That is the only disk space the snap takes up. That compressed file is mounted (not unpacked) in /snap/teleconsole/ and a symlink at /snap/teleconsole/current points to that
alan@hal:~$ mount | grep teleconsole
/var/lib/snapd/snaps/teleconsole_3.snap on /snap/teleconsole/3 type squashfs (ro,nodev,relatime)
alan@hal:~$ ls -l /snap/teleconsole/current
lrwxrwxrwx 1 root root 1 Oct 3 04:04 /snap/teleconsole/current -> 3
At runtime, yes, you will see files in /snap/teleconsole/3
alan@hal:~$ du -hs /snap/teleconsole/3/
However, if you shut the machine down, and examine the disk, you’ll see nothing in /snap, because they only get mounted when the system is started.
So what you’ve done is copy files from the insides of those .snap files to an external/separate disk. The snaps which get updated in /var/lib/snapd/snaps will have new and updated files which you will not have in your copies. You’ve basically broken the snap installs.