Probably you will have to tinker with the ram settings inside your mobo to get it stable. IMO it comes down to you personally. Do you have a lot of programs running at the same time? Than go for the 24GB. But since it’s a planed upgrade you can benchmark your favourite games befor swapping, so you will see the difference yourself.
I have been playing videogames since 1992. Went through almost every controller design possible. From the modern ones, I never liked the layout from the playstation so sticked to Xbox. At the moment I’m using a GameSir T4 Kaleid and absolutely loving it. Mechanical buttons and hall effect joystick are very nice. Since I’ve had it only for a year I can’t say anything about reliability. Most reliable Xbox controllers in order are Xbox classic controller S, 360, One. After that every single one is bad IMO. Series controller start to drift pretty fast, same as both elites. So at the moment my most favourite is the Xbox One controller 2nd revision (1708) also known as Xbox one S controller but if the GameSir won’t break for the next couple of years it will be the top one for me.
I hope more first party controllers will get a proper higher tier version with real reliable parts like everything hall effect and mechanical buttons…