HDMI display backlight automatic dimmer

Hello, my player is almost done, one of last things i did, is to control HDMI display with relay. Display is simple IPS Waveshare 800x 480 HDMI with backlight switch. I just soldered two wires and connected them to relay. Relay is controlled by Volumio Amp plugin. So far works perfect. If plays light is on, when stopped then off.
Nice to have would be not to turn it on/off but slowly dim by time, 2-3 sec would be enough. And vice versa when play is on.
Little problem is that i have only + line, not gnd, something like automatic potentiometer or so. I would appreciate any idea


do u use the touch display plugin? @gvolt is this possible? i believe it already is dimmable…on time

Yes i do, display itself works good, just this will be nice to have

This only allows the backlight to either power on or off, but no dimming.

Yes, i know , then i asked for some automatic potentiometer, if i added manual one, it worked