Hello, On IPv6 the DNS is not propagated over DHCP, custom DNS server or automatic from ISP, client does not receive any DNS server ...on IPv4 everything is ok.

@Kevin_Z ...no, there are no qos settings, I've done two times hardware reset, no special setting, all defaults, I have a small apartment, all devices are in 3m distance from router, birds view, no...

Hello, ...after update to latest firmware, my tablet Samsung Tab S7plus, connected over 5Ghz Wifi6, wpa2, is not capable more than 50~60Mbps download, but 600~700Mbps upload, also my phone Galaxy S20...