FSL/NXP is on 6.1.4 and TI is on 6.3-rc2. ST seems harder to find, they look like they're merging 6.3. Is that close enough?

I think so, thanks.

Last time a looked (which was a long time ago), most other SoC's led you down hyper-version-specific patchy nonsense to Linux to run on them. Good to see the field is improving :)

Getting mainline on their Yocto recipes is tough, those tend to lag way behind. But anything is possible if you bang your head against those recipes hard enough.