A Pinta snap is available with a much newer version, but I’m going to ignore it because you specified the deb package.
The takeaway here is that it’s not an Ubuntu failure of responsibility. It’s a lack of Debian volunteers. A lot of volunteer help is needed at Debian to fix the blockers and the bugs and thence to get an upgrade into the pipeline.
My advice to everybody led here by a search engine: Pitch in! Contact that Debian maintainer team (Debian CLI Applications Team) and see where your skills can best help. Commit a few evenings to learning how to fix one of the problems. Just a couple hands can get the pipe unclogged and running clear.