That's not the case for a long time. I have rEFInd that started life in windows 7 esp with freebsd dual booting, now the same hard-drive booting windows 10 (upgraded from 7, not fresh installation) and nixos, all with the same rEFInd from the same.
The correct way to do so, is to have separate hard-drives for different OS. Then there is zero chance of them stepping on each other.
The correct way to do so, is to have separate hard-drives for different OS. Then there is zero chance of them stepping on each other.