i ask if it's possible to install 2 os on raspberry and during the initial phase choose which start. Now i have installed debian on raspberry pi 4 with 2 Gb Ram and 64 Gb sd card.
do you have any suggestion?
Search these forums for "dual boot", I found several threads, but as I haven't done it I wouldn't know what to suggest, but at least it'll give you some ideas until someone with more knowledge replies.
it's better to have separate sd cards with what ever os you want & just swap them when you want to play with something else.