Ok, new router and an AC wireless adapter. The problem is that there are only three channels on the 2.4Ghz range that does not have interference. The new standard allow 5Ghz which has a lot of channels to use.It happened with the previous router as well.
USB AC adapters are very cheap on Amazon and you can get a new AC wireless router for a low cost.
Most new phones, tablets and computers will use AC. The older N standard will do 5Ghz too


