Not sure about Android (since I haven't used that in more than a decade), but on most iPhones, you can have several eSIMS installed - whichever one you use will be turned on, and all the others will be turned off until you are ready to use those again. You don't have to uninstall or remove anything. Of course, on the newest phones, you can use both at the same time.
Android is the same, and I was even looking at esim adaptors recently whereby esims can be used in phones that don't support them. Just slot the adapter into the SIM socket.