This is something that has bothered me since Desktop, and I'm frankly surprised it still hasn't been addressed in Pro:
In my daily workflows, I often find myself needing to run quick little snippets of Python code. They're often not big enough to warrant jumping out to an external editor/workspace, so I just use Python Window on the Analysis tab.
Great! It's convenient, it's fast to pull up...and it uses the same variable-width fonts as the rest of ArcGIS Pro. Really?
Python is indent-based, so I need to know exactly how many spaces are at the start of that line, but in Pro's Python window, I have to drop a cursor and arrow over one at a time to make sure it's actually the spacing I think it is.
Once or twice, I've noticed this window at least partly in a monospace font, but I can't for the life of me figure out how to get it to stay that way. I've also had it do weird things like turn all of the white text (I work in dark mode) into black text—usually when pasting in from an external document—which makes it too easy to lose a colon at the end of a line, for example.