Prevident (by Colgate) is a Rx toothpaste specifically for people with dry mouth. It’s around $15 per bottle but it lasts a long time & has really helped me. Biotene, suckers, hard candy (peppermint & lemon flavors help with nausea too).

Get some Biotene 👍

Lozenges, Biotene, Rinsing with baking soda & salt mixture, tongue scraper

ACT makes a lozenge for dry mouth

I've used a baking soda, salt and warm water rinse/gargle during the day and night which I l also use for mouth sores. I think it's 1/2 tsp baking soda, 1/2 tsp salt and 8 oz of warm water. I've heard sucking on peppermint candy can be helpful too. Water intake seems fine.