Currently on Android, sim questions

I have 3 nano sims ( UK main, two lowest cheap sim plans for other countries). If I wanted to visit another country and use the sim for that country, and get an esim for data, would I need to take the UK sim out physically? Is it possible for example, converting the other country nano sim into an esim, and use 2 esims for data and calls?

Currently I'm on an S24 ultra, so since it has 2 slots I just turn off the UK sim and turn on the other sim, and esim for data when visiting other countries, how would this work on iphone? I'm not most familiar, thanks