internet blockage problems after port forwarding on asus gt routers

hi all. new to the forums posting but been reading a lot over the past few years.
ive looked all over the forums on anything remotely close to my problems ive been having over the last few weeks. so here goes and ill try and explain everything in detail as best as possible.

I had a asus rt-ac5300 for awhile as my main router and never had much problems out of it outside of the occasional reboot to get everything back up and running on the wifi as I have smart plugs/smart light...

internet blockage problems after port forwarding on asus gt routers