OH! I just clicked around in the interface, we now have independent AP isolation back again, but with A LOT more control just like I requested half a year ago in this thread. Thank you TP-Link!!! You are the best :)))) Now I can finally stream to my Chromecast without having to turn off my smart lamps (being worried if they will be a security risk). Amazing! Now there's also a dedicated IoT network, but why bother when you can isolate every single device you want? That's a little confusing to me. But I digress. Amazing update, 100% wonderful :)

Edit: Confusion gone as per this thread - No need to enable IoT network, just isolate high risk devices.

I noticed that the CPU usage went up a bit (10-20%) after the update.

Turns out, the firmware enabled LAN Flow Control TX without my knowledge. I have no need for that, I have maybe 6 devices connected at once at the most. CPU usage went down again to 16% average. My model only has a dual core mind you ;)

Tether app also have new features all of a sudden, but I rarely use them. I still can't figure out how to completely disable Homeshield, which this model isn't even supposed to support (hence why I picked it). It's in there in the Tether app for some reason though.