I commented elsewhere in the thread that one option that can mitigate limited RAM for some users is to get a fast, dedicated NVMe swap device, stick a large pagefile/paging partition on it, and let the OS page out stuff that isn't actively being used. Flash memory prices are up too, but are vastly cheaper than RAM.
My guess is that this generally isn't the ideal solution for situations where one RAM-hungry game is what's eating up all the memory, but for some things you mention (like wanting to leave a bunch of browser tabs open while going to play a game), I'd expect it to be pretty effective.
dev tasks, builds…etc
I don't know how applicable it is to your use case, but there's ccache to cache compiled binaries and distcc to do distributed C/C++ builds across multiple machines, if you can coral up some older machines.
It looks like Mozilla's sccache does both caching and distributed builds, and supports Rust as well. I haven't used it myself.
https://www.youtube.com/watch?v=SJwh3erQlyE&list=RDSJwh3erQlyE&start_radio=1