How to choose a snap program to always run when clicking on tel link?

Hi all,

the title is probably not so accurate, but my problem is really simple:

When I click on a phone number online, I can choose zoom to always run so I can call this number with zoom.

However I want Skype to open this phone number so I can call it.
However I installed Skype as a snap.

when I enter ‘skype’ in terminal, Skype starts as expected.
When I enter ‘whereis skype’ in terminal, I get the following output:

skype: /var/lib/snapd/snap/bin/skype

When I go into thunar, I can see these directories exist and everything is correct. I can find the Skype executable.

Here is where things get difficult:
When I try to choose a different application to open the tel link in firefox, a window opens where I can select a program to open these links, and I can supposedly browse to the Skype executable.

However when I then go to /var/lib/ the ‘snapd’ directory is not there, instead there is only a directory named ‘dbus’.

Maybe this is because I installed firejail?

Anyway, how do I solve this problem? I wish to choose skype instead of zoom

thank you