If you are going to do it, practice it away from traffic to find out the braking and steering limits with engine off. There is usually enough vacuum for assist with two to three brakings. The lack of power steering becomes poor of an issue at slower speeds. But cars differ. My new Sonic has electric power steering, and, at least the turbo engine, has a compressor/accumulator for the brakes. I have yet to lose either power braking and steering with it while EOC.
Then done it only when safe to do so. Such as not doing it through blind bends.
I wish cars gave the option to turn power steering off, you dont need it over 10 MPH anyway with todays light, small engined cars. Ive had a fair few cars without power steering and the feedback you get from the road is fantastic! But as you say, most cars now use electric motors, which ease off at speed anyway.