This looks nonsense to me. I had everything switched off and stil problems. When in Access mode,none of the third party options are available!

I agree! see: https://forum.tp-link.com/showthread.php?110123-Deco-M5-stops-working-after-last-update.

Model : Hardware Version : Firmware Version : ISP : Since the last update (1.2.1 Build 20180606 Re. 52910) I have noticed that the internet connection on all my devices fails from time to time. I...