I support what the others say, it’s cool if you can pay, but it’s not a must IMO. If you’re fine with the base tier, or can’t/don’t want to pay for more, there’s no shame in that.
Shelter works fine to keep two accounts, which should be enough hopefully, otherwise you will have to use the web client.
There was an experimental app that allowed you to have a potentially unlimited number of duplicate apps (twoyi), but it’s sadly discontinued, there’s also another called MultiApp, but there’s something yiffy about it I can’t quite put into words