Got around to trying to unscrew the l shaped bracket and in very tight. Will try some wd40 on it.
Found one source of rattle : an electrical connector towards the lock bashing against the door over bumps. Some double sided tape hopefully to sort that out.
And a lot of play in the blue thing that holds the window and moves up and down the slide rail. Seems to be only at the bottom of it. Will try and tighten the bottom nut, as I have read. People seem to mention other fixes , but I don’t understand them so far.