1 mg sublingual (dissolve under the tongue) melatonin works for me. I find it works best if I wait until I'm well settled in and should be asleep, but aren't. That's the time to quietly pop the tablet so it nudges me over the edge.

Biggest problem is that 1mg sublingual is hard to find. Walgreens/CVS is excited to sell you 5, 10 even 20 mg pills and gummies. But, those are so strong they are counter-productive.