We do see that opiates can mess up the HPTA. Opioid - Wikipedia
When the hypothalamus and pituitary are working right and T levels are low, LH and FSH can be quite or very high trying to get the testes to produce T. If your testicular function was weak from varicocele only, your LH/FSH would be higher, not low.
Lab normal ranges are statistical normal curves where a range includes a arbitrary 95% of samples in a sample group. This is not typically a not a optimal health range. However cholesterol labs, fasting glucose and A1C are now reported as optimal health ranges. There is a lot of resistance to making such changes as health programs and health insurance companies would be burdened with costs of treating new conditions. With glucose and cholesterol a clear case was made that overall costs to the systems could be reduced by focusing preventative medicine on those labs.
With LH/FSH, sample groups include guys that have no apparent health problems. But those samples do include guys who have low T levels who are not doing very well and that cause can be lower LH/FSH. Lab normal ranges include a lot of people who would say that they really do not feel that great.
Never assume that in-range means OK or optimal. Assume that almost all doctors will make that mistake.
If your LH/FSH were higher, you T levels probably would increase. But it is possible to have primary and secondary hypogonadism at the same time. One way to know would be to do a trial of a SERM or hCG as a diagnostic, checking TT, FT, E2 levels later. There are more details to this and dosing should not be high, a common doctor error.
I get the impression that the percocet is not medically necessary. If so, you really need to get off of that train.
Your T has been going down for years. So it is progressive and cause unknown. May be a combination of things. Prolactin needs consideration and repeat labs should involve avoiding orgasms, cuddling {puppies | kittens | babies} for 3 days as that releases prolactin.
We have a lot of guys your age with low LH and FSH. How many in the general population is unknown. But young tech savvy guys find there way here in a large proportion.
You are cherry picking your responses. Please read all of the first two stickies.
Do not ignore the thyroid issues!
TRT is probably your best window of opportunity to the life values you stated are important to you.