On a bicycle if you can modulate the brakes so it never loses grip and you adjust your balance you can use both brakes in corners - I’ve been doing it most of my life, sometimes at speed and have done it on extremely steep slopes to avoid trees and obstacles. It’s possible without the rear wheel being on the ground at all, just never lock up or lose traction on the front wheel but that takes (sometimes painful) practise.

It doesn’t feel as good as decelerating before, and is most definitely not as safe as you clearly explained.