My L2 MTU has been changing through builds.. it's now @1560 was previously @2290, I've read 2290 is a thing so left it alone.
What should be the best L2 MTU for WiFi ax products it's very confusing.

I join this question.

That's in release notes for 7.12:

*) wifiwave2 - limit L2MTU to 1560 until a fix is available for a bug causing interfaces to fail transmitting larger frames than that;