Post Android 9 update, connectivity issues

[Volinus]

Two of my apps stopped working completely because it couldn't connect to servers. 

Browsers become sluggish and often hang up. 

Can't load captcha or sign in on many pages, (even on sony site, need to sign in via fb instead).

This is the worst update ever since I used xperia phones.

Update:I tried to pinpoint the cause, it seems the update messed up the connectivity, wifi 2.4 is totally toasted, 5 can't handle anything other than YouTube. Apps that require internet connection are screwed, either end up with Java exception error or timeout.

Yep, I already tried factory reset and software repair via Sony companion, nothing is solved.

Seriously connectivity is the most basic thing which must not be screwed.

[Volinus]

It's definitely the update. I cross checked with other networks and devices. Only this phone affected.

Laptop and other oreo phones work fine in the same WiFi network. 

XZ premium "sometimes" work properly when tethered to mobile Hotspot from other phones.

When will you fix it Sony? It's obvious that the cause is your update. And don't give me bs like this update magically renders your phone incompatible with your router so you have to either buy a new phone or a new router.