You can put multiple accounts on the same device. My wife and I share one switch.
We used to have one per person, but I don’t play as much and we hardly play at the same time so I sold my other switch.
Physical games are sharable but it also means you can only play one device per cartridge at one time. So with games with only 1 save slot, you should get more physical cartridges.
Digital games are locked to the account that bought it. Anyone can play it, but if it has one save slot, then that will be the biggest issue.
Can you play doom on your calculator app?
With this you can play doom on your emulated calculator!