Connection problem (wifi only, netgear router) Steamdeck

[omg it smigu]

I have a weird problem with R6220 Netgear router, at least I assume so. I can't connect to Github, and Helldivers (that is helldivers one) servers. I do not have this problem when connecting via cable to the same router, or via wifi with phone hotspot. I did set NAT filtering to Open in WAN setup. I did autodetect onb the ipv6 settings. My Steamdeck has a static IP, and I even set this IP as DMZ in WAN setup. Any ideas what else to do?