Devices disconnecting every 5 minutes

[New5]

Hello . We switched to EE in October from Sky and have had disconnection issues from the WiFi hub since it was installed. ( Essential Fibre 36 ) 

The lights on the hub never change but basically we will lose connection every day several times a day. Sometimes it is literally just a case of only one tablet being used at any one time as soon as the other picks one up, it disconnects as it cannot cope with 2 devices. Leave it a few minutes and you can get back on albeit at a very slow speed initially ( speed checks show anywhere from 0.5mb to 5mb) but then eventually back to around 19mb. 
Devices are mobiles , desktop, Printer etc. Only 2 people in household. No TV streaming . So not exactly pushing the limits I wouldn’t say. 
6 Engineer visits so far. 2 In house from EE and 4 openreach. Line tests fine every time but the last 2 openreach showed us the screen which showed the router keeps disconnecting every 5 minutes or so which they said isn’t right at all so a new router was sent. 
Exactly the same with the replacement so nobody seems to know the answer!  Sockets checked by openreach ( master socket no others in house) 
Every time we contact , it apparently shows as a definite fault at EE CS end but yet openreach say absolutely no faults and EE cs don’t understand what they are seeing basically. 

Although we have had many line problems in the past (being end of exchange and part fibre it is slow anyway)  but these were all identified and fixed as trees rubbed through but the faults were complete loss or intermittent with router lights going off.
This is completely different and I am not sure if it is coincidental that it started after switching to EE hub or is there a reason it could be just this hub as honestly  if the engineers cannot understand why, I definitely don’t!  We are able to leave as the guarantee was 30mb and we don’t ever hit 21mb but if it is a line issue, this doesn’t help either. 
Any help really appreciated!! 

[Mustrum]

@New5   Is there any chance you can get a service from anyone else that does not use Openreach?

If not you could raise a complaint to EE to see if you issues can be resolved?

Or switch to a supplier with a good reputation for resolving tricky fault conditions, alas they tend to be a little more expensive. You could look at A&A or Zen as a couple of examples.

[New5]

Thankyou for your reply. I cannot imagine so as we had a job to get the main providers! Basically SKY didn’t want to renew our contract as the line maintenance was so costly ! They would renew but at £50 + for basic broadband package. 
Frustratingly fibre is now only less than a hundred metres away but as we are one property , they won’t bring it down to us as the current line takes the longest route imaginable through trees and across a major road to get to just us.But to be fair we have never had any issues previously with openreach via sky and it was always fixed. This time we had a couple “ fresh out of school and ideas” but the last couple were very comprehensive but could not work out why the line shows perfect ( although that surprised us as it has never been that!) but their screen shows it is losing connection constantly and resetting every 5 mins or so. 

[Mustrum]

@New5   you could check the Ofcom availability site, or your preferred comparrison site to see if other suppliers are available. https://checker.ofcom.org.uk/en-gb/broadband-coverage 

But if engineers are showing disconects every 5 minutes, they should be able to work out where.

And if your speeds are lower than they should be it suggests a line problem somewhere. Maybe they just don't want to replace it, or can't get trees trimmed.