These help me
OraCoat XyliMelts Dry Mouth Relief Moisturizing Oral Adhering Discs Mild Mint with Xylitol, for Dry Mouth, Stimulates Saliva, Non-Acidic, Day and Night Use, Time Release for up to 8 Hours, 40 Count https://www.amazon.com/dp/B007XEVQ8G/ref=cm_sw_r_cp_api_i_TBTWW6FH81F6C3RVZT3N?_encoding=UTF8&psc=1
You may be breathing thru your mouth. Consider buying a chin strap to keep your mouth closed.
Xylimelts also helped me
OraCoat XyliMelts Dry Mouth Relief Moisturizing Oral Adhering Discs Mild Mint with Xylitol, for Dry Mouth, Stimulates Saliva, Non-Acidic, Day and Night Use, Time Release for up to 8 Hours, 40 Count https://www.amazon.com/dp/B007XEVQ8G/ref=cm_sw_r_cp_api_i_G5WJV3C1PFB12A3YXA25?_encoding=UTF8&psc=1
Someone on this sub recommended these to me and they work pretty well. The directions say to stick them on your gums but with my trays in it's not very comfortable so I stick them to the roof of my mouth. They dissolve quicker but it still works.
I would also recommend "XyliMelts" if you haven't tried them yet. They're oral-adhering discs that stick to your teeth or gums to relieve persistent dry mouth, lasts 1-6 hours. You can take'em during the day and/or while sleeping (use at least 2 while sleeping) - works way better than any gum or mouth lozenges. You can choice between "mild mint" flavor, or neutral. https://www.amazon.com/Oracoat-8-55933E-11-Xylimelts-Count/dp/B007XEVQ8G/ref=mp_s_a_1_1?dchild=1&keywords=xylimelts&qid=1612895541&sr=8-1
a lot of people like these to avoid dry mouth:
and to avoid all day bad breath, get one of these:
I haven’t had a cold yet but I use thesethese for dry mouth. I leave the aligners in and have not had an issue with damaging them. Sometimes my throat also gets dry and sore (before and with aligners) and I’ll use thesethese with aligners. Only one every few hours but no issues with staining.
What country are you in? I get them from Amazon because most stores don't have them. I like the ones with mint in them, but they make one without mint, too.