Have gone through all the typical steps so hopefully this might bring up some alternative strategies.
Have a wholehome mini wifi set up connected to a Plusnet HomeHub (Sagemcom Plusnet HomeHub One). It's a small house but it's long with very thick walls so I have 5 separate wholehome mini hubs.
1 x Lounge, plugged directly into the router via ethernet
1 x Hallway (-68)
1 x Kitchen (-43)
1 x Spare bedroom, through an ethernet power adapter that goes to the router
1 x Bedroom (-68)
(listed as they get further and further away from the source)
Generally the network is pretty stable and for most of my devices I've had no trouble. Except for a (recent model) Google Chromebook that's probably the most important device in the household right now as my partner is using it for teaching lessons.
This drops off all the time. i.e. it dropped off today within 15mins of restarting the entire network although most days it tends to do this either if you move through the house, in the morning when you start up again or within 24hrs of the last restart. Which led me to think it might be a DHCP issue - I've now assigned it a static IP via the main router and changed the DHCP lease time to 21 days. No change to the problem, still happens all the time. This problem is also not solved by restarting the chromebook. The only thing that works is resetting all of the wifi.
I also had a very strange issue last night where every other one of the wholehome mini nodes just disappeared and only the main one was live. Even the second one plugged in via ethernet disappeared. This wasn't a problem that purely affected the Chromebook, everything went down. But generally most of my Apple devices are fine day to day (with the exception of last night).
To add to this my network map is a little odd. The bedroom (good connection -68) is currently a sub of the kitchen (good connection -43 signal) but there are two very thick walls in between them, it should really be linked to either the spare bedroom (ethernet) or the hallway. However the internet speed is still strong (68mbs down, 18 up which is about what my main router is getting). Channels it's using are 1 & 48.
The advice to leave it on for a couple of days to settle doesn't really work. 1. We tried this over the weekend and over Christmas and 2. If the device can't connect and restarting it doesn't help, we don't really have an option to get her teaching her lesson.
Hoping there's some help as the constant resets throughout the day are getting quite testing!!