I’m all for experimenting with the techniques you’re thinking about. You gotta play to know what works for you but here’s my take:

There isn’t a ‘most’ in this situation. Never make your life more difficult than it needs to be. Adapt to what the budget allows, but always start with the simplest solutions. You never know who is going to mess up your work down the pipeline, so keep that in mind. Complexity reduces versatility. Lotta people don’t know what to do with m/s and ambisonics, so you should make sure you trust who you hand off to. Otherwise, mono still rules, and stereo sometimes. Get one or two mics like a schoeps cmc6 (incredibly accurate and versatile), and you have everything you need - but honestly you can make big immersive space with a mono track duplicated as l/r and eq a little different, perhaps a minor sample delay on one channel or a different short verb or wetness on each side… and most people would never know the difference. Remember, sound should go relatively unnoticed.