Live Room vs. Control/Mixing/Listening Combo Room-Acoustics Forum-Acoustic Fields Forum

I’m in the daydreaming/idea/planning stage, so I’m fortunate enough to not have any restrictions of room size or ceiling height at this time. I’m working to design a studio for home use plus occasionally having other bands (primarily 3-5 piece rock/blues) to use the space for rehearsing and recording. This room/building is far away from neighbors where soundproofing is not as critical as in a city/suburb. I’ve read a lot about avoiding 90 degree angles and finally came up with a potential layout to fit a control/mixing/listening room on one side with 3 isolated rooms for vocals and/or isolating guitar cabinets, then a large live room for the drums and rehearsal space. Then, I came across a post on here that mentioned that the front and side walls in a listening room must be perpendicular. Now I’m confused. I think a lot of information out there doesn’t differentiate between live room acoustics and mixing/listening room acoustics. Under which circumstances is a rectangular room preferred? When, if ever, do you slope or vault ceilings? Do the suggested room ratios change between live and mixing rooms? I appreciate any direction on how to clear this up before I plan too much detail with the wrong layout. Thanks!