Some time ago we bought, at great expense, a supposedly very good Showerlux shower door - 8mm, good and strong; the works. Within not long the door became very dirty looking and mottled; no amount of cleaning would remove it.
I contacted Showerlux to receive the terse response that it was all my fault as I had been using propriety cleaners on it and not their own special stuff suited to the coating that was on it.
We were refurbishing the en-suite this year and had hardened ourselves off to buying a replacement door.
However, first I consulted Co-pilot - the AI app on my new computer, and he/she/it not only knew the problem but also the answer, about which we were a bit sceptical.
Anyway, with only about £40 to lose we bought some cerium oxide on line and some felt pads for the angle grinder, followed Co-pilot's instructions and, hey presto! - we are still amazed we have a perfect shower door! Every morning it is a joy to stand and stare at this pristine glass. It's a a bit prosaic I know, but thought I would share with you in case anyone else has a similar problem.