Firefly III is missing plenty of features (see below). I started Firefly III with a single user (me) and everything else is a bonus.

https://docs.firefly-iii.org/firefly-iii/about-firefly-iii/w...

I will admit that I caved under pressure and built the Firefly III Data Importer:

https://github.com/firefly-iii/data-importer