In the meantime I moved, decided to build a bigger crabitat and did just that! Given that I already posted it on the subreddit I thought y'all might enjoy it as well!
First off:
External dimensions are 200x170x80cm, with internals ebing 200x130(including substrate)/100(without substrate)x80cm, we have a 40cm headroom for lamps and technical stuff.
Over all it took me about 3 months to build, and another couple to finish given that I started studying and was lacking some time. The crabs are having an absolutely crazy blast in there, changing shells whenever they feel like it and being as active as they could possibly be. It's still not quite finished, but it's getting close. "Once the pandemic is over" (a man can dream) and I have easy access to all stores again it'll surely move faster.
As always, feel free to spam me with questions and I'll gladly reply!
Also don't mind my formatting, I don't think the forum appreciates 100+ pictures in one imgur gallery being in one link so I'll just provide the link. If it should work with (url)... then please tell me as the preview does not seem to work.
Edit: just so you have at least SOMETHING to look at in this post
https://imgur.com/a/d5BWyYa