I would drink enough to be comfortable, at minimum. You're probably not going to do yourself long term harm by dehydration (assuming you drink enough at other times through the day) but you will lose quality of sleep, which will make your feel less rested over time and probably make your overall bedwetting situation worse. I'm in the same boat as you (I don't wet every night, and limiting fluids is helpful but not foolproof) and decided a long time ago that, while I will certainly refrain from drinking a huge glass of water before bed, I'm not going to torture myself into going to sleep thirsty for an outcome that still isn't 100% certain. I've found it helps late at night to quench my thirst with a sports drink (Gatorade or something like that) rather than just plain water, because it keeps your electrolytes in balance so that your kidneys don't just immediately funnel the extra water into your bladder. If pure Gatorade is too strong then try diluting it 50/50 with water. (That tastes kind of weird but that should help discourage you from drinking too much!)

It may seem like drinking a few sips makes you wet as badly as a gallon would but it's not really true. Give yourself enough time to get used to it and your wet nights will probably revert back to a similar amount to when you weren't drinking anything. Obviously it's best if you just drink enough to avoid having your mouth get too dried out, and limit it to that. I'm sure you also empty your bladder religiously before bed, but try getting up just ONE extra time (not 5 or 6 times -- it's tempting but more than once really is no help!) and empty your bladder again, maybe 1/2 hour after lying down but before falling alseep. When you lie down at night it signals your body's metabolism to "shut down" for the evening, which tends to result in a bunch of urine being processed through your kidneys all at once. So, if you can get that first half hour's amount out of your bladder before going to sleep, you have that much better chance of getting through the rest of the night. Again, it's not foolproof, but every little bit helps!

Good luck, I hope you can figure out something that helps for you soon! You're definitely not alone with this!

I just started dating this girl, who happens to be a physiotherapist, and she gave me this advice

so there's this thing called pelvic floor exercises to strenghten the sphincter muscles, all you have to do is sort of tense or squeeze your buttocks, hold it for at least 10 seconds, and release
: you do that as often as you can
it takes a while to see/feel the effects, but it does help, it helped a lot of our patients with spinal cord injuries, stroke, etc.

I just drink what I like and wear a good absorbant nappy at night.

not drinking at night not work
i pee the bed every night and even
if i not drink anything at night
i still pee the bed

I remember my mom talking about this with her sister and her point was that when I’m diapered thick enough I should drink as much and when I like. My mom never limited it. I often drink before I go to bed because I feel thirsty.

Same for me. no matter what I do, drinking or not, I wet the bed. So I drink when I feel thirsty and trust my diaper.

Funny how there's no logic to it:
you can go out for a drink with friends or have a glass of wine at a meal and be soaking - or dry all night.
Or abstain from liquid for ages and be dry - or soaking.
As kids we never drank after 6pm - and were always soaking!!

i drink stuff right before o go to sleep
and if not i drink stuff right before o go to sleep
i will still pee the bed