I have no plans of ever getting a swtich (DRM concerns, plus the inability to back-up saves without hacking), but I have played the first two Disgaea games on the PlayStation 2. So, here are some thoughts:
* These games are SRPGs; the battles take place on a grid, and there isn't any real exploration outside of combat. (There are a lot of story sequences, of which I believe most (not all, unfortunately, at least on PS2) are skipable.)
* One famous aspect of the games is that you can reach level 9999, and can eventually get your stats into the millions (though you will need powerful equipment to do so). However, the final boss is only around 100 (if you don't get any Stronger Enemies bills to pass the Dark Assembly); the extra levels are really only for postgame.
* Each weapon type has its own skills, which are learned by using that weapon in combat; different classes get weapon mastery faster than others, and it varies by weapon. There's also magic, of course. Skills can level up by use, though that mechanic feels like an afterthought (especially for healing magic, which grows in cost but not power as it levels). Skills use SP, but in Disgaea 1 and 2, your SP eventually gets so high that there's no way you could realistically run out. (Disgaea 3 and 4 have a way of upgrading skills that boosts their costs exponentially, so large amounts of SP can run out in those games; that feature has other balance issues, however, like defense and HP becoming useless as they won't let you survive an attack.)
* Your characters can lift and throw other characters, enemies, and even geo symbols (see later in this post).
* One notable feature is the Item World. This feature, which has some of the feel of a roguelike, has you going through a world inside an item. Each item has at least 30 floors, with rarer items having more. (Note that alnist any item can appear at any rarity, so you can find legendary cakes and sodas; yes, they have their own item worlds, but be aware that they disappear if you eat them). (One thing to note; the game does not handle the full inventory condition gracefully.)
* Also, geo panel puzzles. There are geo panels on the battlefield, which are indicated by color (which does create an accessibility issue for colorblind players, though being able to see the effects when you move the cursor over them mitigates them somewhat). There are geo symbols, and if one of them is on a geo panel, all panels of that color will have the symbol's effect; some are good, some are bad, some are nasty (enemy boost x3, enemy level up 10% each turn). Destroying a symbol will change every panel of the color to the symbol's color, destroying any other symbols on the changed panels in the process (creating a rather satisfying chain reaction). In story levels, these are sometimes used as puzzles; you might even run into a level where making a mistake can result in a softlock (entire map invincible). Geo panels and symbols also appear in the item world.