Hi @Alexandre. Wow, that is what I call comprehensive and helpful advice. I happened to have another switch I could use to test, so that made it a lot easier to test your hypothesis. Although I...

@TP-Link Deco I have bought 3 Deco S4 units, all of them are connected via ethernet cables. I am using access point mode because I don't want a deco unit in my fuse box where the signal comes in...