I had a software update not too long ago. I think ever since then, I've had WiFi issues. Like things won't load right when I have WiFi on and I don't think it's the network connection.
Does all the other devices work well? Do the other devices have working and perfectly fine network?
Did you also try wiping the cache partition? https://support.t-mobile.com/docs/DOC-24999
You wiped it after the update or before?