That has been my experience too. Although I haven't had great success with melatonin, I do better with .25mg that I do with 5mg. Larger doses leave me feeling terrible the next day.
Another poster on here had some success with "Linear Progression for Sleep" a few years back:
"Linear Progression" for Sleep: a trial of sleep restriction therapy
I've been dealing with sleep issues for probably 20 years now. Usually not very serious, but every couple of years I experience a bout of insomnia where I sleep very little (maybe two hours per night) for a few weeks. It's a truly miserable experience. Presently I find that I am waking up for a couple of hours in the middle of almost every night. According to my Fitbit I am averaging about eight hours of sleep, but it is taking me about ten hours to do it.
Like you, I've had very limited success with OTC sleep aids. I too find that they lose their effectiveness after just 1 or 2 nights. I am not even a little bit interested in prescription sleep medication. I've read that they basically anesthetize the brain and render you unconscious but don't really provide any restorative sleep. I have a friend who has been taking Ambien every night for years. Watching her is like watching
Night of the Living Dead. She is going through life like a zombie.
I've read that cognitive behavior therapy might be the best bet for serious relief - at least better than medication. I've found a few CBT apps that claim to provide some benefit, but I haven't been able to find an in-person therapist. Maybe if you live near a big city.
Finally, nasal strips are a godsend.