On the Github page you linked it says under Installation: “Clone the repository and install the required dependencies enlisted in requirements.txt.”

It seems like you didnt do that…

Lemmy is developed, run and largely used by open source enthusiasts; FreeCAD is too. Thus I dont find it particularly surprising that open source communities (such as FreeCAD’s) were quick to open a Lemmy community.

If you dont care about privacy, what advantages are therw with proton over tutanota? Proton also has apps for all these platforms…