(I have already posted this message as a reply to the wifi disconnect thread but starting a new thread to give more visibility to this finding and workaround)
I have found a solution for the wifi problem on my Nokia 8.
First of all, the problem I had was that while browising internet pages or with any ecommerce app or internet radio streaming suddenly and silently the internet connection would simply stall and pages would not load anymore until I switched wifi off and back on or waited for some 20s or more and then reload the pages. This would repeat every ten minutes on average. Extremely annoying and pushing me almost to go and ask for a refund. Please note that in the very same environment and at the very same time a bunch of other devices would work with no issue at all: iPad mini 2, iPhone 6, Chromecast 2, Huawei P8 Lite 2017, Huawei P10 Lite, Xiaomi mi A1, three different Asus laptops from 2012, 2015 and 2017, and even the original Samsung chromebook from 2012.
Here I have a Fritzbox 3272 ADSL2 router which acts as my primary wifi access point then I have a switch and two additional access points by TP-Link, one in the basement and one in the upper level. All are 802.11b/g/n.
I changed the settings of the Fritzbox from 802.11b/g/n to 802.11b/g and now it works great, I can stream internet radio for one hour or more with no disconnection at all.
I have not changed the secondary TP-Link access points, they are still in 802.11b/g/n mode and when my Nokia 8 switches to them then I have the wifi stall problems.
So clearly it is related to 802.11n and there must be some software timer either in Oreo 8 or in the wifi chipset that every 10min or so tries to upgrade the link to 150Mbps but fails.
I can change all my home routers and disable "n" but what about when I am at work, at a public conference or anywhere else?