Internet speed over wifi is very slow and ipv6 has no internet access

HI, I am using windows 11 , my system experiences very slow internet speed over wi fi , but when I connected it to the ethernet of the same router, The speed is up to the mark. In my settings, I've noticed that my Ipv6 has no internet access. I've tried troubleshooting, network reset all these options , still don't found the solution...