Some comments I have posted before as a primer.. __________________________________________
Assuming your wired connections are all ok, (are they?) then getting your own wireless equipment should solve any wifi issues permanently, and will be transferable to other BB suppliers kit should you move supplier.
Get either..... (1) A Mesh System, (2) A Wireless router, (3) A Wireless access point or (4) A combination of (2) & (3).
I would say a good Mesh will be the best/simplest/most flexible for most average users. A Triband system is better for the "backhaul" and for users on high speed packages and umpteen simultaneous connections.
It depends on your requirements for... better routing features, your house layout, size, construction materials, your tech abilities, and of course, budget, ~£60-80 will get a decent introductory wireless router but 'may' not alone solve the wifi in your house, but spending up to ~£500 will get the “Rolls Royce” solution of a high-end Wifi6 Router & WAP's or a top end Tri-band Mesh system. You'll probably want something suitable - somewhere within that range - I reckon ~£100-150 is around the “sweet spot” for most standard users, and where you would probably need to start for a standard 2/3-story house if it has brick walls. Less for a one-bedroom modern build flat, more for a stone built 8 bedroom mansion
Good options for Access points/Wifi routers/Mesh systems come from Ubiquiti, Asus, TP-Link Deco's M4/M5, Linksys Velop's, Tenda Nova's, Netgear Orbi's (and others) – I would stick with these companies whose business this is - rather than “newcomer” and data-driven” companies like Google, Amazon, etc. Also be sure the router or Mesh specifically says that they have 1GB ethernet ports - some of the cheaper ones only have 100Mbps ports.
Recently, just as an example... two of my friends who both live in brick built 3/4 bed semis, both just got TP-Link Deco M5 3-packs (~£150) and both told me it is - “absolutely brilliant with full wifi speeds in all rooms, the attic and the garden, and the App is a doddle to use”. The first Mesh unit becomes the new router - you need to check whether the one you look at has all the "features” you need. Ethernet ports are usually limited to 1 or 2/unit , so you “may” need to add in an unmanaged GB port switch (<£20) in there as well. My mates also get "full speeds" from the ethernet ports on the Deco's in the remote locations. Finally if you get a 2/3-pack of any Mesh system, which doesn’t cover dead spots everywhere, you can just add in extra unit(s).
Take a look at what fits your needs, tech ability, house layout and budget. Use sites like Techradar & Techadvisor for reviews of "Best Routers" or "Best Mesh". Post again if you want personal recommendations from others on your short list
-------------------- John --------------------
I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router +2 Airport Express's. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.