Good morning @chopperdave. I’ve been where you are for 5 years including sleep studies, sleep specialists, meds etc. so I understand how it affects your life. I will be 71 next month and was told by a sleep specialist that this type of sleep disruption is “normal” for about half of those over 65. About half my friends in that age group have unsatisfactory sleep so that statement seems to be true. Seems that hormone imbalances/declining hormones are significant factors in sleep. Are you on any medication or supplements at this time? I find that the older I get, the more sensitive I have become to side effects. Supplements that are somewhat stimulating such as Rhodiola or Alpha Lipoic Acid even when taken in the morning seem to affect my sleep that night. Have you been tested for Vitamin D, B12, iron and ferritin levels? All other lab work OK? Do you refrain from looking at screens such as smartphones, laptops etc at least an hour before bed? Do you turn off your Wi-Fi at night and leave your cellphone out of your bedroom at night? Lots of studies published in this regard. Have you tried prolonged release melatonin such as Douglas Labs brand? Do you refrain from any caffeine after morning? Even caffeine in the morning can affect some people’s sleep that night. My mother started experiencing insomnia in her early 50’s if she drank any caffeine (chocolate included) or consumed any sugar or too many carbs after 6:00 at night. I’m the same way except now, the small amount of caffeine I may consume has to be in the morning only. And as mentioned by @gloaming, do you get any exercise outdoors during the day? There is a great book “Spark- The Revolutionary New Science of Exercise and The Brain”
I hope this may have given you some things to think about.