A few lives ago I started my professional career by trying to sell custom office software. Having opinions about that kind of stuff I've chosen Python and PyGTK and some NoSQL database library and it's been quite a struggle. In this present moment I live as a digital nomad traveling neutral zones around World War Z and I use many different online services in my professional life and all desktop clients for them are super shitty, starting with google-built web browsers. And whenever I consider building a kind of desktop utility those programs are there's a lot of resistance and comparative lack of tools (in comparison with what web backend context provides). And a lot of primary consumers for some of those services (think collaboration services) are educated, experienced, and opinionated folks like myself. Perhaps there's profit in coding desktop linux software again? And combined with my backend proficiency I could be weird full stack dev services developer... I should explore it. Sounds very meta.
Making different versions of PyGTK libs being easily available in venv and pyenv would be a great start. UI / integration testing tools (including running headless under multiple environments). Ability to install such "apps" with pip or some equally simple manager (not "sudo this long script we provide"). I'm pretty sure most of this already exists, I should just explore the space and develop a coherent process and see if there are any gaps. I did have some idea for a collab tool, actually. But I won't tell.