FPS? while it's a TPS, try Splatoon 2
As for RPG, Xenoblade Chronicles 2, obviously. Also, give Golf Story a shot, really worth it. The Grandia I and II remasters and the Final Fantasy remasters might be interesting if you missed them before. Edit: How could I only forget Octopath Traveler? Get it! Right Now!
I don't know what other consoles you own, so not sure if I should suggest some multiplat titles which didn't make it to PC.
If RTS includes Tower Defense games, there are a couple of them on the Switch, most notably Aegis Defenders and PixelJunk Monsters 2. Also, there's Constructor Plus and Swords and Soldiers I and II (only played the first one on my Wii U, not bad at all, but totally moronic plot) as interesting RTS titles. Valkyria Chronicles 1 and 4 may be very interesting for you too, as they blend RTS, Turn-based Tactics and RPG into one
Oh, and on a general note, look at the link in my signature. It hasn't been updated for a while now (really need to find some time for that!), but might give you some pointers.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454 List as Google Doc: https://docs.google.com/spreadsheets/d/1aW2hXQT1TheElVS7z-F3pP-7nbqdrDqWNTxl6JoJWBY/edit?usp=sharing
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/
Free Pc Games thread: https://gamrconnect.vgchartz.com/thread/248138/free-pc-games/1/