Need Advice

I currently have sf1200 and having problems with wifi and the nextdns.
Some users can connect to the internet but cant open streaming apps while other devices can. ISP internet is 1000/500 mbps but im getting about 150/60 mbps. Currently using the 3.204 firmware.
Was wondering if I should buy mv1000 just to do the wan routing and use the sf1200 for access only or should i buy the ax1800.
Please help advise.

curious have you tried to set dns rebinding protection off both on the router and on nextdns itself?

also, are you using different subnets on some devices?

I was just playing around with a streaming app on tv, and figured out that there was a blacklisted domain from google in nextdns which made the streaming a black screen something with imasdk do you see that sub domain popup maybe in nextdns logs from google?

as for advice, I’m not certain yet.

Yes. I have disable the dns rebinding at both places.
The router upgraded to the latest firmware now and I cant manage it thru the web browser when connected by wifi.
But the clients can connect to the internet just cant manage the router.

And on cable you are able to access gl-inet web interface?

Can you show me a screenshot of the interfaces and firewall zones and dhcp under the network tab in luci?

by going to advanced settings, the password should be the same as the gl-inet web interface.

Your router gives the only dhcp or does your modem also give dhcp?, There is a setting called Authorative dhcp inside luci, maybe that one needs to be unchecked along with filter private in case you are using different subnets or using a another router with dhcp in the same subnet?, it saved me some troubles.

By Cable yes.

This router is the only one providing DHCP

Another thing is that today I came back home and the router was on but noone can connect to it. Had to reboot it to make it work again. Been rebooting about 4 hr intervals.

Tried removing IPv6 and it works except for Netflix.

I have the travel router mango which is connected to 4g with everything the same except ssid. All the clients work perfect. Everything is smooth. But the sf1200 cant work smoothly. What is wrong?

Hmm, sometimes the logs in luci can show some usefull information, you still got a dhcp lease from the sf1200 on wifi but no internet?, and on lan internet correct?, Or is it that over some time the dhcp fails and wont give any dhcp?, Or dns doesnt resolve?

I know from searching the forums there are 2 issues stubby sometimes stops which uses nextdns you can restart it manual, and I readed some where that the chatty ness of udhcpd with MSG_NO_ROUTE could cause troubles on other subnets see OP: Flint dhcp issue but this is only for openwrt chaos calmer 15.x I believe your router uses openwrt 18.6.x ?

And the wifi interface firewall zone points to wan or is it part of lan (thats fine to) ?, And you use no vpn or wireguard ?, This zone need to be forwarded to if you use a different network interface than the default ones.

Can you turn off NextDNS and check the performance?

It still hangs up and needs rebooting.