Thanks for your feedback,
What does your answer mean - Do you still try to find a solution?
With 0.9.20 I had no problem at all - obviously the new Update had some changes how to handle the controller.
e.g.: you mentioned that Ruida should have even fewer issues with connectivity:
TEMPORARY CONNECTIONS FOR DSP CONTROLLERS
Ruida, Trocen, and TopWisdom users should now have fewer issues with connectivity. LightBurn now connects to DSP controllers only when active. If you run multiple copies of LightBurn and have had issues sending to the laser from your 2nd copy, this fixes it.
However, would appreciate if you could look in to your controller connectivity improvements, if there any conflicts now with the 6445 controller.
Could you please try to find a fix for this issue.
Thanks and have a nice weekend!