They are self-contained for the most part. That AppImage works on many different Linux distributions.
So just how old is your system? Have you thought about updating it?
What version of glibc does it have?
Update:
Based on our github workflows that AppImage is built on: ubuntu:22.04 from April of 2022.
Your version was released in April of 2020 and out of support after May 2025.
So it looks like you will need to upgrade to at least the 22.04 Ubuntu to get things to work.
Code:
22.04 LTS (Jammy Jellyfish) Apr 2022 Apr 2027
20.04 LTS (Focal Fossa) Apr 2020 May 2025