Which of these providers have the best router?

I've been with plusnet since 2013 using their fastest fibre package. They've offered me a renewal contract at £28 for 18 months which is decent, but their router has always been inconsistent with wifi, even when using devices in the same room where the router and master socket is. When I do a speed test in different rooms (two story house) I get 45-55Mb/s. Unfortunately the connection just tends to drop out. I had to invest in a powerline adapter which has a wifi booster connected to it downstairs.

The providers I've considered switching to are sky, ee or bt. BT is expensive compared to the others. Between sky and ee, I'm leaning more towards sky as they've recently launched their new broadband hub. I haven't considered vodafone as their reviews seem to be bad overall and I've read a comment on here saying that talktalk have a good router, but they're the only isp I had a very bad experience with years ago and I don't think I'd consider them again.

Your help is appreciated.

I have the impression that your objective is to improve your wifi. How close is your house to other properties? Have you tried running some thing like Acrylic Wifi for Windows to find out what other network you might be competing with, especially as you say you can lose a wifi connection to a router in the same room

Powerline adapters can work but they are certainly not always successful.