Someone made a flowchart on what to play after finishing the series.
If you’re willing to check out non-RPGs, then I highly recommend Star Tropics (which is on the flowchart). The best way to describe it as a cross between MOTHER (setting) and The Legend of Zelda (gameplay). An interesting thing to note is that Star Tropics is a first-party Nintendo game that’s never been released in Japan despite being developed there.
Another thing is that there’s a point where you’ll need to get a password off of the Internet. The game originally came with a letter from the protagonist’s uncle that contained the password, which would only be revealed by dipping the letter in water.
Jet Set Radio
It’s through Proton, but the game runs flawlessly. Do note that you’re really going to want a controller for this one. Playing this with a keyboard is a miserable experience. Another thing is that there’s an unofficial tool for importing images over your custom graffiti, but it’s for Windows and I’ve never tried it with Wine.