General help - wifi & lockscreen

hello everyone
i have some question I hope you can help me
1- when I have some active apps in background like steam or firefox while downloading game , after screen timeout screen doesn’t turn off it goes black but still on and in my lcd monitor its clearly visible , is it a bug ? and what can I do about it ?
2- most of the time i’m using my phone with hotspot to connect to the internet and while in setting i disabled metered connection in software and other apps it shows my connection as broadband and disables auto updates via that network , is there any setting or command line to fix this ?

One year later and still same problems in all gnome desktops

Is this a notebook computer?
Have you tried turning off the Powersave option on the Wifi?

sudo nano /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf

You should see:

[connection]
wifi.powersave = 3

Change it to

[connection]
wifi.powersave = 2

ctrl+x to exit, then y to say yes to save, then enter to save as current configuration.