Earlier quoted context omitted.
It crashes a lot on me on both the latest macOS and on Ubuntu 18.04. That said, I'm not one to lose patience on FOSS and know it can and will improve.
Don't really know about macOS, but Ubuntu 18.04 is a distro with, what, 6 years old packages ? There have been a lot of bugfixes to the whole stack since then which will never make it to older Ubuntus - remember than the "stable" in linux distros means "does not change", not "does not crash".
- Krita also crashed on me when Ubuntu 18.04 was recent.
- Most Krita crashes are on startup, before I do anything.
- GIMP never crashes on me with heavy usage. In fact, few graphics manipulation apps crash on me.
- Finally, like I said, Krita crashes often on the latest macOS.
I think the "blame" is entirely on Krita. That said, I'm patient and understand software has bugs; Krita will be stabilized eventually.