I’m nearly 70 and have had insomnia for the last 4+ years. It’s not unusual for a man my age to wake up several times in the night, whether I need to pee or not (I usually do, though). I don’t have trouble falling to sleep initially, it’s the getting back to sleep that often eludes me. I’m told not to look at the clock, on the other hand if I’m awake for 20 minutes get up and find a “relaxing activity” to do until I feel sleepy again. Which is it, look at the clock to know if it’s been 20 minutes or not? However, Non Sleep Deep Rest gives you the benefits of 20 minutes of sleep for every hour of NSDR. Better than nothing. And then there’s the “Damned if you, damned if you don’t” on using/not using a sleep aid like diphenhydramine. It does make it easier for me to get back to sleep, but studies show that constant use can lead to an increased chance of dementia. And constantly not getting a good night’s sleep and lead to an increased chance of dementia. Seems I’m screwed either way.
You’re definitely not alone in this, and your concerns are completely valid. While this isn’t medical advice, just general guidance, here are a few thoughts that may help. When it comes to the “20-minute rule,” you don’t necessarily need to look at the clock. If you feel like you’ve been lying awake for a while and sleep isn’t coming, that’s your signal to get up and try a calming activity — something screen-free and low-stimulation like reading a physical book, stretching, or deep breathing. As for diphenhydramine, you’re right — it may help in the moment, but regular use can carry risks, especially long term. On the other hand, chronic poor sleep has its own health consequences. It’s a difficult balance, but this isn’t the end-all be-all — there are gentler, more sustainable strategies out there like CBT-I, light therapy, or even occasional melatonin under supervision. Small, steady adjustments can often make a big difference, and there’s hope even when it doesn’t feel like it right away. 
I saw my doctor yesterday and we’re going to try trazodone. Wish me luck.