iPhone running SUPER slow on home wifi. Please help.

My iPhone 6s Plus has had this issue for a while where it will be very very slow on my home wifi to the point it won’t load YouTube or online games but it will be perfectly fine using data. It also works fine at other places with wifi and has no slow down issues. My home wifi did not used to have this problem. Just all of a sudden starting having an issue. Can a compatibility issue come out of nowhere like that? I have done all the trouble shooting short of getting a new router. Nothing fixes it. Any advice?