I'll usually buy controller upgrades if they're available. Like the Wiimotes that came with Wii Motion Plus, the Wii Classic Controller Pro, the Switch Pro Controller. I also own a couple third-party controllers for consoles that the Big 3 never made themselves, like a fightstick.
But I rarely buy upgraded consoles unless they have big features or solve a hardware problem I had with the original. I used the original 3DS during the entire generation, I used my launch-day Switch for the entire generation, and unless the Switch 2 gets a HUGE upgrade, I'll probably stick with my launch-day Switch 2.
I think the difference for me is that console upgrades are kind of intangible. They can release a Switch 2 with a better screen, but I could also just connect it to a monitor. They can release a PS5 Pro with better hardware specs, but it still plays the same ol games. They can release an XBOX with the power of a supercomputer but it still won't have any games ;)
But controller upgrades are extremely tangible. I can feel the difference, and it feels different in every game, on every supporting platform. And there's a good chance this same controller will be supported on the next generation of consoles, so I can use a nice premium controller while I wait for the next-gen premium controllers to go on sale.
I never bought any special plates or anything though. I was interested in the idea of them when the original New 3DS came out (not the XL), but wasn't interested enough to buy one lol.