In regards to you possibly upgrading what games are you playing that you're finding are pushing your setup to it's limits? Or is it mostly After Effects?
I play Skyrim with mods, Rivals, CounterStrike, Session, The Forest, rarely i'll boot up COD. I run at 1080P with ray tracing turned off, smoother lighting, cloud/fog/mist effects enabled if applicable.
It's mostly AE though, it's difficult for my machine to render more than a few minutes of footage at times, it'll crash and I wont be able to continue working on the original file so I am constantly backing up to an external SSD to at least kind of pick up where I left off. Doesn't overheat or get loud with AE, the program just crashes.
Also forgot to mention I run Yuzu as well but only for BOTW or TOTK as I enjoy online with some Switch games.
Sick idea with the cabinet too. I modded my old PS Vita and 3DS for my partner to play GBA/Color games we can't find.