Square taper has worked fine for me. Only one crank has come loose and rounded out on me in 25-ish years of riding square taper 3-pc cranks.

You don't need to check them every ride. You need to torque them down properly in the first place. I think 300 ft-lbs is a typical required torque and many people don't get those crank arm bolts that tight.

I don't think I'd let the interface make my choice for me. If you can source the exact same crank then you won't need a new BB, though.

Cranks sold with bottom brackets are much more common now than they were 20 years ago.