My experience with flatpaks has been mostly good. I tend to opt more towards .deb based apps, with flatpak being a fallback option. With that being said, the Pycharm Pro and Spyder flatpaks don’t run well at all on my system, with Pycharm being too heavy, and Spyder crashing due to Kvantum incompatibility.
I commonly use the following font families:
Hack
Noto
Inter
Helvetica
Montserrat
Space Grotesk
Times New Roman
Atkinson Hyperlegible
Cormorant (Garamond)