I have here one RB5009 and four cAP ax access points.
For LoRaWAN and a few IoT devices, I also have a LR8.
The cAP ax APs are managed via wifiwave2/CAPsMAN, but I can't find a wifiwave2 package for the LR8.

Is it somehow possible to manage the LR8 via wifiwave2/CAPsMAN? How?

No.

LR8 can not run wave2 driver (neither wifi radio nor mipsbe platform are supported, doesn't have enough RAM nor storage). And no, wave2 CAPsMAN can not control legacy radios (and vice versa, legacy CAPsMAN can't control wave2-driven radios).

You can run both legacy and wave2 CAPsMAN in the same L2 network, but not on same device.

Thanks for the fast answer, even tho I don't like it

Is there any newer device available/planned, that does support WIFI and LoRaWAN and wifiwave2?