Wow, you sure have been experiencing a lot of problems lately. I've started to wonder if you've fundamentally messed your system somehow by tinkering with something you shouldn't have.
I'm not trying to be insulting. I know you are a very compent long time Linux user, and that makes it all the more baffling. I have no idea what's going on with your system of late, but something seems amiss.
Anyways, back to your current dilemma. Perhaps try installing inkscape-git to see if it provides any improvement.
Actually, after lots of toiling and bubbling brews, I found a solution, and the problem....which is kind of on Garuda, I guess.
I did try and build the .git version, gave me Gentoo PTSD, as it takes ...FOREVER. It ended in errors, so it never worked. I then looked at Poppler and noticed that on my laptop where Inkscape works I was using the 'Poppler-glib' from the extra/repo. My PC was using the version from Chaotic-aur. I switched it out to the extra version, and boom...BOOM, Inkscape opened and ran. So, someone on the G-team might want to look into it.
Thanks for your reply and help. I am off to vector-ize some art.
I now have poppler-glib version 21.10.0-1on both systems from the "extra" repos .
The one that breaks Inkscape is from chaotic-aur 'poppler-glib-git' version 21.10.0.r14.g24d0445a-1. I think this is the version that is pulled in when you select Inkscape for install with Garuda's setup assistant.