How you make the bewbs physic interact with cloths like you did here ?
Tried it and I either get a) Horrendus physics going to infinity or b) take 4h to just preview a single frame... and I have a good computer.

i've baked simulation on just body first, then I've baked simulation on just shirt. not both at same time
(looking at the file, i've used softbody at the time, but since then i've switched to clothsim, mainly because of baking simulation being (usually) faster)

usually when baking, when i see blender being stuck on one frame for longer than usual (you can see it on blender's timeline), i usually try to cancel the baking (with Escape key), review what went wrong in the sim, tweak parameters and/or model, and try baking again.
also, don't go overboard on 'quality steps' both in overall cloth settings and in collision section of it, try lower those values at first and increase only if simulation 'explodes'
(higher 'Quality Steps' = more accurate simulation, less errors, longer simulation time)
(lower 'Quality Steps' = less accurate simulation, more chances for 'explosions', shorter simulation time)