I went over to GitHub and grabbed a previous version of Trezor Suite (the previous version was GPG verified as GOOD too). It fails to perform producing similar errors as the current 21.3.1.
Here are the errors reported below. One instance was me as user trying to run AppImage in a user terminal. Second was me elevating to sudo in a terminal. There was a third instance where I actually went full root using a root terminal but it produced the same result as my user invoking sudo so I didn't paste it here.
Reminder: Right clicking the Desktop AppImage Icon and changing the properties dialogue to executable and then clicking on the Icon does nothing.
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user@debian:~$ cd Desktop
user@debian:~/Desktop$ ./Trezor-Suite-21.3.1-linux-x86_64.AppImage
[1980:0320/195209.105776:FATAL:setuid_sandbox_host.cc(158)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now. You need to make sure that /tmp/.mount_Trezor7lPlMN/chrome-sandbox is owned by root and has mode 4755.
Trace/breakpoint trap
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user@debian:~$ cd Desktop
user@debian:~/Desktop$ sudo ./Trezor-Suite-21.3.1-linux-x86_64.AppImage
[sudo] password for user:
[2082:0320/195504.314527:FATAL:electron_main_delegate.cc(253)] Running as root without --no-sandbox is not supported. See
https://crbug.com/638180.
Trace/breakpoint trap
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It appears that I will simply wait a month or so (to get out of beta) before getting involved with Trezor Suite. A Virtual Machine running Debian Buster AppImage doesn't like it so far! I don't want to run this on a bare metal machine so I don't know if the VM is introducing variables into the mix causing these errors.
ps - I am not involved in this project at GitHub. If someone wants to copy and paste this to someone there feel free to do so. I don't mind experimenting with things in my VM's if getting hands on would help them at all.