We use Community Fibre which was fine in Bowater House and we now use in Stanley Cohen. You say you have a router, you should have a Moden too. I hope that helps
I have been with BT for years. It is not full fibre, I think it is fibre to cabinet. When I first moved from Cullum Welch to Great Arthur there were a few teething problems but that was over 4 years ago and I have not had any problems since. I get download speeds of about 75 mb/s and uploads of 18 mb/s. Not as fast as full fibre but I have a lot of devices connected and often work from home and I never lose connection, unlike a lot of my colleagues who have full fibre and have had a lot of issues. .