Alright, we're one step forward, ty! It doesn't keep restarting and looping, but a new problem has arisen. It now gets stuck at:
Installing breakpad exception handler for appid(arma3server)/version(1.0)/tid(107)
I don't know if it is genuinely installing something and I remembered in the original post of the docker you did mention it takes a bit for first time install, but when I googled that line it seems there are others who end up getting stuck on it. However those other cases I don't think are necessarily server setups, so I wanted to ask if you have run into this one before?