Help on complex custom dungeons-only dimension?

Hello all, i'm in need of some guidance.

I'm trying to create a dimension that only contains air (already done), but will generate an infinite complex of connected rooms. (I have no clue on how to do this.)

I've googled some forum threads similar to this, but they were really old and really vague.

If it helps to tell you, I've already got the room schematics part done. I've built different hallways and basic square rooms, all have varying shapes and sizes but all the entrances/exits are 3 blocks in width and length. (entryways and exits are 3x3 so everything connects somewhat seamlessly)

I just need some help with the whole "getting rooms and hallways to randomly generate and connect" part.

Lastly, i would want to add biomes that, instead of affecting terrain that obviously doesn't exist in this dimension, it affects the rooms that would be generated in the dimension

Cheers.

To give you a better idea of what im trying to make, look up "the backrooms".