I'm interested what ROS versions are being considered stable for WDS and nv2. Please post your experience.

you can use station-bridge instead of station-wds.
I would recommend to use RouterOS v6.10.

I have had problems with "wds". The network is comparatively slow. Although I have tried using devices in pairs.
And sometimes I find the network broadcasting too much traffic. I do not know how to tackle that.
I have had much better performance with station bridge. But yes... I have read at many places that "wds" works better, I am yet to figure out how.

you can use station-bridge instead of station-wds.
I would recommend to use RouterOS v6.10.

Could you explain why station-bridge? From manual, describing station-bridge:

This mode is safe to use for L2 bridging and should be used whenever there are sufficient reasons to not use station-wds mode.

So I switched to station-bridge and I did notice longer uptime for wireless connections and quicker reconnect (I did not test performance however). I use 2.39 firmware with 5.9 ROS for stations and 5.14 for AP btw.