Hi,
I never used manual (fixed) channels for APs.
I’ve always put on auto, also for power.
Some advice that we use:
On 2.4 minimum multicast rate 12
Mode gnax
Airtime fairness ON
Enhanced roaming OFF
Dynamic Channel and Dynamic power ON
On 5 minimum multicast rate 12
Prefer non DFS channels
Mode default
Airtime fairness OFF
Enhanced roaming OFF
Dynamic Channel and Dynamic power ON
For start, every other settings on default.