@TP-Link Are you still around?

@TP-Link thank you for your reply Decos connect each other via wifi, they are on the same floor in a line. And around 7 meters each. I can put them together, use short cables connect them.

The deco M5 is so unstable, sometime is normal, but most of the time is only 1/4 speed of direct connect to isp. I upgraded to latest firmware and downgraded to older versions, but none of this solve...

@Big-Dream same here, is there a way we can reverse back to earlier version