My and my wife's GS9s have recently run into a frustrating problem. The device's operation, app loading speed, app refresh speed etc all crater when connected to a wifi.
Turn the wifi off and they run normally.
I don't believe it's our internet connection or signal strength to the router. Download speeds in the browser are very normal. App operation though, again, is badly affected.
It takes 1.5 minutes to upload a screenshot to gmail. Strava crawls and will load some pages but fails on many. Hulu opens after 45 seconds of splash screen. Some apps hang in the splash screen permanently.
Have you tried turning off everything that might interfere with sending and receiving data when connected to the Wi-Fi network?
I have the following options turned off.
Switch To Mobile Data
Turn On Wi-Fi automatically
Detect Suspicious Networks
Wi-Fi Power Saving Mode
Secure WiFi
Wi-Fi Scan Throttling
The last item on the list is only available in developer options and least likely to be causing the issue. I've had issues in security and battery saving features that meant well but slowed everything down or interrupted the connection long enough to trigger a lost connection.
If you haven't already done so try to wipe the system cache partition.
I haven't heard of any issues related to the randomized Mac address but you might want to set it to phone Mac address while testing.
@Clf thanks for your reply and advice. My wife and I have both been having the same issue and I've been using her phone as a control against what changes I try on mine (much to her dismay).
Things I've tried:
Restarts
Soft Resets
Forget Networks and reconnect
Reset Network Settings
Wipe System Cache Partition
Turn battery from optimized to high performance
Turned off "Put apps to sleep" (This caused issues about 6 months ago with app performance, symptoms unrelated)
Turned off Adaptive Battery
And now, all your recommendations above for network preferences. No improvement unfortunately...
Some apps are severely degraded, other apps seems unaffected...
All other devices in our house run at normal speed. My phone's browser even runs at normal speed and performs a nominal internet speed test without difficulty. Something in the phone is severely throttling data movement within certain apps and the internet when connected to any wifi network
