CCQ at 90-95% is very good.
What kind of stability problems do you have? Do the links disconnect, lose packets or do you mean unstable signal parameters?
I have a running ptp link whit, as we speak, 95/93CCQ, but about 1 hour ago, it was down on 60-70%. I kicked out the client so I it had to reconnect ant the link is up at about 95% again.
But I have another ptp link that is between 60-90% ccq. would an upgrade help to better/more stable ccq?
Probably one thing you must keep in mind: They changed something with RSTP (and till now undocumented). So bridges sometimes hangs with enabled RSTp
Despite this Mikrotiks with nv2/ROS 6.19 and enabled wireless-fp works very well.
waiting for 6.22 where are fixes due to kernel crash. (in 6.19 stil persists, but not so annoying like eg 6.15)