First of all, I commend you for your commitment to physical fitness. It is hard work to be in shape and maintain that level of and us.
My input is so minor that I almost hesitate to post it, but I whereas I used to be able to drink caffeine up until 6/7:00 PM, I noticed it was interfering with my sleep, so I cut back to 4:00 PM as the stop time for no caffeine. I know you said you don’t drink caffeine in the evening, but I am wondering if you drink some mid afternoon. For me, it is now about 10 years after noticing for the first time that I was unable to fall asleep after consuming any caffeine at all (including chocolate) or alcohol so I think I’ve become extra sensitive to it. If I’ve had caffeine too late in the day, then my symptoms are similar to yours, I feel tired physically, But I just can’t seem to fall into the drowsiness that leads to sleep even though I feel I am on the verge of it. I don’t exercise like you do however, and since you worked as a personal trainer you have an extensive knowledge of the importance of bringing active & healthy.
It is true without adequate sleep, everything kind of goes haywire, and it is hard to be alert & fully functional. Good luck with getting answers that lead to better sleep.

Have you ever thought of compression pants when you train?