Changes in THAT interface (dev tools) are not intended to be propagated to the syswand are for testing purposes only. What that interface is doing is just force overwritinv the value in the database and it will be updated the next time the device reports status.
Consider the media player read only. You’re not actually updating its status you just want it to display differently - and that tells us what you need.
What you’re looking for is a way to override what a card says on the UI not the media player entity itself…
Its complex but you can absolutely do that with card mod. Go surf the card mod thread, I’m almost positive there’s media player examples.