When I started with Linux, I was happy to learn that I didn’t need a bunch of separate partitions, and have installed all-in-one (except for boot of course!) since. Whatever works fine for you (-and- is easiest) is the right way! (What you’re doing was once common practice, and serves just as well. No disadvantage in staying with the familiar.)
After I got up to 8GB memory, stopped using swap … easier on the hard drive -and- the SSD. (I move most data to the HD … including TimeShift … except what I use regularly.)
I use Mint as well; for me this keeps things as simple as possible. When I install a new OS version (always with the same XFCE DE) I do put THAT on a new partition (rather than try the upgrade route and risk damaging my daily driver) using the same UserName. A new Home is created within the install partition (does nothing but hold the User folder.)
To keep from having to reconfig -almost everthing- in the new OS all over again I evolved a system. First I verify that the new install boots properly, I then use a Live USB to copy the old User .config file (and the apps and their support folders I keep in user) to the new User folder. Saves hours of reconfiguring most things. The new up-to-date OS mostly resembles and works like the old one … without the upgrade risks.