The first time I had ceramic done (9 years ago) I also had the glass done. It was bad. Couldnt see anything in the rain. Had it removed.I like Rain-X too. Used it back in my uni days (over 20 years ago). I read there are more modern products that get more than a few months out of them but am yet to commit to applying any. Gtechniq G1 Clearvision is probably top of my hit list atm.
When I got my graphene coating, they were meant to have applied a glass product on the windscreen. I didn’t ask which one though. It doesn’t seem to bead like Rain-X but then again I haven’t really driven at speed through rain.