I mention bits and pieces on my app's blog [0]. But more interesting to you may be a Wiki I created on GitHub with the things I had to learn about PyQt the hard way [1].
[0]: https://fman.io/blog
Oh, and you may also be interested in a video I made of my app's release process on Win, Mac and Linux: https://youtu.be/uhIj9B2At28
We made a MVP using Electron but had to ditch it because of performance issues. PyQt seems like the best alternative, but the pain points you described were hard obstacles in the beginning.
* We gave up on making Omaha work, after some wasted weeks, and are using pywinsparkle to autoupdate on windows.
* The QSS feels buggy all around, the "border-radius" property is one of the simplest examples of that.
Would greatly appreciate some open-source solutions, examples or simply some blog posts of best-practices and how you are managing these pain points. :)