It took some time for me to find a way to use my mars2 printer without using any proprietary software, so I figured I would post about it for other people to whom it matters. The goal here is to replace Chitubox/Lychee used on my computer, I did not mess with the printer itself (meaning: this is not about flashing the printer's firmware with a libre alternative).
The slicer I use is prusa-slicer. As far as I know, it's the only libre slicer handling SLA. Funny enough from what I read, some people already use it for