Regain your privacy! Adopt /e/ the unGoogled mobile OS and online services
I currently have the s version of the system installed. could I install the R or Q version without losing anything installed?
very unlikely this works, some “state” in settings databases could be incompatible and bar you from a successful boot. Then there’s the “rollback protection”. You’d need to backup your userdata and reflash.
How can I make a backup copy?
that is very much do-it-yourself, as in copy images via usb cable or if you have them uploaded to murena.io or any other webstorage that works too. You’ll need to reinstall apps etc