Vitus Sentier Donor Bike - chainring sizes

Hi all, I’ve read through numerous posts and still struggling to grasp what will be the best size chainring for BBSHD for my current setup.

I’m running a SRAM SX Eagle 1x12 chainset. Front is a 30T 170mm ring, cassette is 10-50T. I wanted the option of running pedal assist and also throttle only and maybe even sometimes pedal unaided. (Am I asking for too much?)

What would be my best sizing option?