I did not expect issues with folate either. Have been playing soccer very hard all my life and 2 years ago at 47 was still competing with 25 yo on the pitch. Then I ruptured ACL for the second time, and only due to that had to stop playing. Still had plenty of energy, but the knee took long to recover and required second surgery to partially remove damaged meniscus.
I have been having sleep issues similar to yours from time to time for many years.
My conclusion is do not ignore low folate for too long. Just add liver regularly (not only for folate) and take 5-MTHF - it may further improve other health aspects as well. I suspect and have some information that folate deficit may lead to gut permeability due to gut lining cells being unable to be built properly.