I don’t think I’ve seen this specific situation posted before but my new Roku streaming stick+ works for most of my tv functionality except for volume control. The power button and mute button work fine so when I go to test the remote (with the music playing and stopping) it says the remote is connected. The volume control buttons (up and down) do not work however. My tv brand is RCA and I see the blue light blink when I hit the volume control which seems like some signal is being received but the volume won’t change.
Reprogram the remote for your tv but skip the first positive code, by saying no and see what subsequent codes do for your tv.
I just tried that and none of the other codes work except the first one.
Re-pair your roku to its remote, then when setting up the tv tell it you have a LG tv?
I tried all the LG codes too and none of them work