This is very informative so thanks for this!

You sound like my brother! He absolutely adores Persona and has been trying to get me into the series for a few years now.

Completely forgot about the Lego games. My nephews used to love them when they were younger so this is probably a good shout.

You should definitely add Octopath Traveler to your list, but if you start with Xenoblade, don’t be shy with the expansion. It’s a pretty good addition to main game once you complete it.

I hadn't heard of it until today, but I'll definitely check it out. Liking the aesthetic from the screenshots.

I'd like to second cycycychris' call for Snipperclips for you and your kid. It's about as kid friendly as it gets, and it's some of the most fun I've ever had playing co-op with another person. I played it with my girlfriend to get her into games. It was a great bonding experience. If I had kids I would definitely play it with them. Aside from that, if you want not only to get him something he can play, but that you can play with him, Kirby is great for that. It's always been a great beginner platformer and Star Allies is no exception, but is fun to play with friends. Captain Toad is pretty easy and I believe has a multiplayer feature now so you could play that with him too but he could play by himself no problem I'm sure. Another one like that is Yoshi, typically easy, but if he gets stuck there's a multiplayer mode and you could jump in. Odyssey has a two player mode that would let you help him by being the hat. So if it's too hard for him, you can give him a boost. As he gets better at platformers, you could eventually show him Donkey Kong Country Tropical Freeze. It's harder, but it has a Funky Mode where you be Funky Kong and are way more powerful, and also has multiplayer. Then of course there's New Super Mario Bros. Deluxe, which is another multiplayer game that has difficulty levels based on characters, with Nabbit being a playable invincible character and Toadette getting a powerup that allows her to survive pitfalls. If you want to get him into RPGs, Pokemon Let's Go is easy and also has co-op that would let you help him. Can you tell that I want a kid of my own and that I have every intention of introducing him to games and playing with him? If you want to give him a game to play by himself, and don't have it on another system, don't forget about Minecraft.

For yourself, since you like wRPGs, FPS, and RTS, you don't have a lot of exclusive options. Pretty much no wRPGs are exclusive, you have Mario+Rabbids for strategy (turn based, but really good, don't knock it till you try it), and Splatoon for shooters (not first person, but still pretty good, pretty fun). Non-exclusive options, besides Skyrim, to look into include the two South Park games for wRPGs, Civilization VI and Valkyria Chronicles for turn-based strategy (there are no RTS Switch games yet, at least not at retail, not until they port Pikmin anyway), and Doom and Wolfenstein II for FPS. If you branch out to JRPGs, your options are way better. Exclusives include Octopath Traveler, Xenoblade Chronicles 2 (and it's huge DLC that's practically a new game in and of itself), The World Ends With You: Final Remix, and the upcoming Pokemon Sword & Shield. Non-exclusives here include Dragon Quest Builders, Ys VIII: Lacrimosa of Dana, and Undertale, and the upcoming Oninaki and Dragon Quest XI.

If I had to recommend stuff regardless of your listed taste, I'd say get Smash Bros. if you haven't already, it's fucking amazing and just about anyone can enjoy it. Fire Emblem is probably worth looking into for you when it comes out, will have strategy and RPG elements. Also don't underestimate Super Mario Maker 2, also coming out soon. Platformers might not be your favorite genre, but damn if the people in the first game didn't come up with some of the most creative shit imaginable. People made complex physics puzzles, turn based combat systems, bullet-hells, and even a battle against a giant mech you could go inside of, all in Super Mario Maker. It was insane. Nintendo will never top it with a mainstream 2D Mario game.

Towerfall is awesome!

Super Mario Odyssey

One of the best games ever made! Took me nearly 50 hours to 100%, which is pretty insane for that kind of game.

Mario + Rabbids: Kingdom Battle

But to correct someone else in this thread: It is not a RPG, it is a turn based strategy game, the gameplay is more or less exactly like X-Com

I imagine there's a good chance you've played Okami. If not, then I can't recommend it enough. Very similar to the 3D Zelda games. Beautiful HD graphics, involving story, lots to do, good integration of some touch screen controls.