screen turns off after 30 secs when on Lock Screen no matter what the setting is

In Terminal try this command & copy the out put here...

pmset -g

Here's my output...

System-wide power settings:

Currently in use:

 standby       0

 Sleep On Power Button 1

 womp         1

 halfdim       1

 hibernatefile    /var/vm/sleepimage

 proximitywake    1

 powernap       1

 gpuswitch      2

 networkoversleep   0

 autorestart     0

 standbydelayhigh   86400

 sleep        0 (sleep prevented by configd)

 hibernatemode    3

 disksleep      0

 ttyskeepawake    1

 displaysleep     0 (display sleep prevented by DVD Player)

 highstandbythreshold 50

 standbydelaylow   0