One thing I'll throw out there is that I've recently been running IntelliJ using jdk 17 with ZGC as the garbage collector, and it seems snappier. (You can use the 17.0 runtime that jetbrains releases on github, this page has more related info https://mustafaakin.dev/posts/2021-12-08-running-intellij-id... )
We might have different definitions of "just fine".
On my M1 Max MBP Jetbrains Rider stars in under two seconds. Loading the quite large project takes another two.
On my previous laptop, an i7 MBP, it took in the order of minutes to get Rider to the point where I could actually start writing code with codecompletion. It sounded like a jet taking off while Rider blasted all cores at max to enable the smart completions.
The M1 Max isn't even slightly warm in the same case. Haven't found out a single spot where it would've even slightly stuttered.
On Big Sur at least there are dozens of daemons running that can't be turned off due to the read-only system partition. I'd check those and third-party software that could be sapping performance. Gets more important with older hardware.