If it were me, I'd rip the old nav screen housing out of the dash and fashion some kind of cover plate to cover the hole, then take it to an upholstery shop and get the dash done in leather - probably wouldn't be all that expensive. If that were prohibitively costly, then I'd just get one of those "dash mat" things that are custom-fitted for the car. Then source a base Business CD head unit off Ebay on the cheap, code the car accordingly, and drive happy without that abomination sticking up out of the dash.
'08 Z4 M Coupé LM08602
'19 Golf R