I have seen on Pinta’s bug tracker and on many forums users are having stability and freezing problems with latest Pinta 1.7 released few days back, see release notes: https://www.pinta-project.com/releases/1-7 and the main cause of it is Mono 6.10 should be installed. Installing latest stable Mono from PPA: https://www.mono-project.com/download/stable/ and Pinta is super stable.
The main problem is: every Ubuntu versions currently officially supported are having its own version of Mono and every Mono version installed as default on Ubuntu-s is outdated for Pinta 1.7. Snaps package would be perfect fit for fixing this kind of dependency hell problems. And Pinta is very nice simple image and drawing tool. Perfect fit for beginners and simple image editors.
How hard is it to create Pinta snap? It should probably package Mono 6.10, some Gtk libraries and Pinta itself.