I have noticed a significant slowness every now and then in my Sense network. Mobile games like Clash Royale lag a lot when I use Sense network (normal or 5ghz). I still have my old non Sense wlan up and running and on that everything is running smooth.
Every now and then I get no internet notification on Sense network and during that time my old wlan is fine.
So something fishy about Sense and some types of data flows...
Sense is connected to router with lan and I use a 24mb adsl connection.
See if you can reconfigure your network so that the router in front of SENSE runs in bridge mode with WIFI disabled and SENSE would be providing the primary wireless networks in your home and would act as the primary router. Let us know if this made any difference.
Please also provide the make/model of the router in front of SENSE and the name of your ISP so that we can understand if this is some kind of interoperability issue or something else.