@Bilski
I have two Win10 desktops and both work with Deco mesh just fine. The older one can only run on WiFi 2.4GHz, I had to enable Guest Network with 2.4GHz only to let PC connect.
This is my Deco mesh WiFi configuration:

The problem you see is most likely at your PC and its WiFi adapter. I suggest you try what I did, for troubleshooting. If that does not help, googling for generic WiFi connectivity issues on Win 10 computers could give you ideas of what to try next. For example, check this: "Available WiFi networks not showing in Windows 10"
I can't share external links in that form, but it is from answers_microsoft_com web site.