Sure, I could probably get ROCm going after a lot of tinkering and headaches but...that's not where I want to spend that effort.
Would happily be proven wrong on this by the way.
Using the Radeon VII for ML was still pain, but I had more free time back then and was willing to tolerate the tinkering. The support for the 5700XT never came, was just constantly led on by AMD devs on their GitHub.
I didn't really have that kind of free time when I wanted to upgrade, so buying 3090s ended up being the only realistic option. Even on Linux, as long as I'm not trying to stick to the latest bleeding edge kernel, the closed source drivers work very well. Thus far I feel the 3090s have been well worth the extra cost simply in terms of tinkering time saved.
It now currently drives my primary monitors, and I keep a second GPU, a 1080ti, plugged in and passed through to a VM. I can then operate the 1080ti as a "program" from my desktop, which is fun, but somewhat limited given the space constraints in my case. Extra benefit is it can also be used for gaming. Next steps might be to toss 3090s in a dedicated chassis under Proxmox, but then I lose the part time gaming use case.
The path to >40GB VRAM as a hobbyist is tricky, but I have to remind myself that even having it as an option is wild.
What are you doing with your 3090s?