Amazing! Thank you for such detailed reply — I'm glad to see overlap between my list and the goal posts (it's an awesome list).
I agree with the click outside dialog, it can definitely be a problem for many. I'll think about some ways that it can be useful but also accident-proof it.
I'd be happy to contribute for #6282. I read the code contribution guide, but let me know if you have any good example for a PR (so I can try to replicate it).
I'll also consider opening an issue with a list of potential mouse shortcuts. I think we can find good inspirations from spreadsheet softwares (e.g. Google Sheets) so non-technical users can use the tool intuitively.