Appimages from proprietary messaging apps

Ive been looking for ready-made appimages for Skype & Viber as i dont want to install their shit on my system. id be using them with firejail.
I also emailed Viber about this but they dont care to respond and it doesnt seem easy to convince big corporations like microsoft to create appimages for skype.

Am i missing something? Are appimages already available for any of these?

How do i create them if i want to from the .deb files they provide? The documentation seems complicated to me.

hi someone please help with this? thank you