So no new Logic features until I buy a new Mac.
Well, you could go the Open Core Legacy route, which would allow you to install any newer macOS (at least so far) on your iMac.
Experience macOS just like before
dortania.github.io
There's a wealth of tutorials and what not around, the entire thing seems to be pretty foolproof as well, but without a doubt you would have to spend some time reading and setting everything up.
Here's a rather new of the countless tutorial videos:
So far, Apple doesn't seem to care much, so your Mac will stay pretty much entirely functional (including using the App Store and what not), there's really just very little things you need to look out for (possibly such as not installing updates automatically, but you're not doing that anyway). Logic updates and what not will just work as you're used to.
I still kinda think about doing this to my old Mac Pro, but as it's really old (2010), it might actually be one of the models running into some more serious "glitches", so I'll just keep it as is. With your iMac however, there should be little issues, so it might be worth trying.
Fwiw, if you decided to go that route, you should really check whether all the software you really need is still supported.
Personally, even if I did a pretty huge jump (all the way from Mojave to Sonoma), I experienced rather little issues. The worst thing (by far) being the loss of Native Instrument's Battery 3 (Battery 4 is an offense to human intelligence and calling it an improvement over version 3 is something only imbeciles would do, let alone it's not replacing used instances automatically in older projects, so that's a lot of manual work if you wanted old stuff to still work). Others than that, it might've been some pretty irrelevant smaller plugins, a video player and what not - nothing substantial at all.
But (and that might be somewhat important for you): You may need to check for your Waves plugins, because, while there might be some tricks to expand their life beyond what is the official stance, V9 is really getting old. OTOH, in case you manage to make them work under Big Sur, they may as well be working on newer versions.
One thing is for certain, though: In case you get a new Mac, they won't work at all but need recoverage (I think at least something like V12-13 is required to work on silicon Macs at all). So maybe it could even be a decent idea to extend the life of your machine in case you're not permanently hitting a CPU limit.
Anyhow, and I really can't stress that enough: As this is easily possible with your iMac (doesn't work that way anymore on new machines, which is a horrible shame): Get a dedicated external drive the size of the internal one (could be a rather cheap HDD) and create a bootable external copy of your system (Time Machine won't do that), using Carbon Copy Cloner or Super Duper. Zero need to spend money for registering them, the process is absolutely self-explaining as well, all you need is some time (you better do that overnight, it might really take quite some hours). It's the best security net there ever was for Mac users (which is why it's such a shame they took that away - or at least made things way more convoluted).
Oh, I just looked things up. Not sure which iMac model exactly you're using, but it seems it's one without an SSD as the main drive. Correct?
Because if so, this is one thing you should *really* consider: Exchange the internal main drive with an SSD. Without exaggeration, this is the most significant update to any computer ever. Pretty much everything will feel as if you had an entirely new machine (sure, CPU power is the same, but boot times, program load times, sample load times, etc. - they all will profit incredibly).
There's very detailed descriptions on how to do it yourself on ifixit, but in case you're unsure, there's certainly plenty of folks who would do it for you, and apart from the SSD you slap in, it won't cost you an arm and a leg.
Man, I really appreciate you digging into that!
You're most welcome.
purafied.com
