External Input Button (TRRS/headphone) to wake sleeping OsmAnd screen

[MrE]

Having gone down the route of many button re-mapping apps to no avail, does anyone know how to get a wired button to wake an Android (v8.0.0) screen when OsmAnd is running? After the screen times out, I'd like to have a wired button on my handlebar allow me to 'button-press-to-wake' while not needing to let go. I purchased a wired camera shutter button with a four conductor plug (TRRS) but the current 'External Input>Keyboard' option won't recognize it (when awake or asleep). Any nudge towards solving this is greatly appreciated.