Firefly III: An open-source personal finance manager
github.com
github.com
F3 is very cool and powerful, though it's also strongly opinionated. I used it for about a year and ultimately it didn't click for, but it really hits the spot for a lot of people.
There is, however, the third party firefly-fints-importer[1] which I'm running without any issues.
Firefly III at one point was planning to support SimpleFIN as well but it seems to have dropped off the radar. https://github.com/firefly-iii/firefly-iii/issues/5396
I have been using a spreadsheet but it is really annoying