Hi guys, hoping someone can help as am at the end of my tether!

Moved into a new place back in February. Previously to that in my last places I've been using a TP-Link TD-W8970 router for all my networking needs which has always worked flawlessly.
Decided to make a modest upgrade to the TP-Link AC1200 VDSL router to get rid of the bt openreach VDSL modem and make things a bit neater as the router was going to be in visible sight and wanted to minimise clutter, cables etc.

Since then have had endless issues with networking. WiFi keeps constantly dropping out at random intervals. Will often still say Connected, secured on devices but try to load websites and it will just sit there in limbo trying to load, try and open games or programs and will get message saying no internet connection. Try and reconnect and devices usually just sit there trying to connect for aaaages before they give up and time out.
LAN'd computers will normally work fine, so usually I end up going on my main wired PC and going into the router to restart which usually fixes the problem. For a wile.

Occasionally though it will bork the LAN as well. Been getting home recently and the GF and kids say that theres no wifi. So I go an turn my PC on to access the router panel to restart and it wont even access the router, just sits there trying to load like the wifi does.
Sometimes it will BARELY work on LAN but everything will be suuuuuuper slow. Returns to normal speeds after restart tho.
Sometimes I come down in the mornings and turn my PC on and it will say no internet so have to hard rest the router even though everything was working perfectly fine the night before and nothing had been used overnight in the time between.

Figured I might just have a dodgy router so got a replacement sent out and sent old one back. Was fine for about a week and the issues started again.

Started to think that maybe one of my devices might be the issue so tried each device on its own individually over the course of several weeks. Doesn't seem to matter what device is attached/connected, router still f's up on it's own.

stuck with that router for a month or two trying to figure stuff out. Eventually got really annoyed and figured maybe I'm just super unlucky and got two bad routers in a row.... Stuff happens.
So sent that router back for a refund and wired up my old router with the attached VDSL modem.
Again, all was fine for all of a week or two and EXACTLY the same issues.

I'm at a loss now to think of things to do.
Had two new routers and even my old router is doing exactly the same thing...

I've tried each device individually, tried different chanels on the router, firmware is up to date.
Starting to wonder if maybe I have some localised interference from somewhere?
Or is it one of my devices that keeps borking the routers? I have two LAN'd PC's both windows 10. I have a synology NAS attached via LAN. Wireless devices include a sony tv, sky box, an LG TV which doesnt get used much as in my man cave up top of garden and is always turned off, have a hauwei mediapad tablet, galaxy tablet, galaxy s7, oneplus 6t and an epson printer connected.

Most of these devices were used prior to coming to this new place and never had an issue before on this old router which I am using again now...

It's driving me insane.
I don't think the issue itself is with any particular router, but would dearly LOVE to fix whatever the problem is