To expand on erlinden's reply:
There are two versions of CAPsMAN:
1 "old" CAPsMAN, settings in menu under /wireless, driver package "wireless"
2 "new" CAPsMAN, settings under /wifi, driver package "wifi-qcom" (on Ax devices) or "wifi-qcom-ac" (on Ac devices)
Your new Ax devices use the "new" CAPsMAN and wifi-qcom drivers.
Your cAP AC XL is very likely using the "old" wireless package, that you should replace with the "new" wifi-qcom-ac to make it "compatible" with the "new" CAPsMAN.
Configuring the CAPs is slightly different if the device is Ax or Ac, depending on the complexity of your setup it might be not-so-easy.
There is some "work in progress" for having a "unified" set of settings, but not yet finished/tested, here, JFYI:
Experienced members (like erlinden is) usually point to the documentation as if it was trivial to understand and replicate it, rest assured it isn't, you will need some time and making some experiments to have the setup working.