Samsung S8+ was not performing at the optimum when I upgraded my router to EA 7500 via Starhub. Certain apps like Google Play are taking longer time to initate the download. The internet is working fine on the browser and certain apps and that is why you may not discover immediately.
The most obvious for my case is my Word and Excel app was taking longer time to connect to Dropbox files and unable to download it to process. It will give you no internet connect after some time. WhatsApp take 10 secs longer to start the download.
- You just need to forget the network
- Please forget 2 network channels (2.4GHz & 5GHz)
- Switch off the router for 2 minutes
- Switch on the router
- Connect back to network and key in your password
This may resolve lagging issue and that you are facing. Android Nougat is known to have Wifi issue. Thus if you use mobile network, it will not occur.
Hope the above info helps all. The Linksys support also not sure of the root cause and will recommend this method unless it do not work.
Else you will need to send your S8 back to the Samsung service Centre as it have nothing to do with the router or apps.