RE: Looking for Info before meeting with Doc. Have gathered some data already.
I wasn't getting as much sleep as you, but I had fatigue, "general malaise" my doctor called it, felt lousy all the time, and blood work confirmed lowT.
Over the course of about a year, I had been through blood tests, stress tests, all major systems were functioning properly (except lowT which was the last test).
Along the way I had installed the sleepbot app and collected data for a few weeks which appeared normal.
I actually did start T therapy and was on it for about six months. At that point my T-levels were high normal and I still felt miserable. As I was leaving my doc's office, he was saying after over a year of diagnostics there were no major systemic issues and that is about all he can do for me. Lifestyle and exercise probably have the best chance of improving quality of life, unless maybe I had sleep apnea. He asked a couple of questions about sleepiness, snoring, etc. At that point I stopped, turned around, and waited for him to write the order for the sleep study.
The sleep study a few days later confirmed severe sleep apnea. The tech said severe was the top category but if there was a very severe he would have checked that. I only mention this to illustrate that all the data I could collect using tools I could find on the internet had indicated normal, yet I had severe sleep apnea in a sleep lab test.
My sleep test did show drop in o2, but average across the night was about normal (I wonder about the granularity of your o2 metrics... average over test period is not useful, periodic dips associated with apneas do the damage. I don't know enough that this might be a dumb question since I don't have a recording oximeter I don't know how they work. maybe they all show granular time interval stats).
In my exeprience T therapy has given me a notable improvement but it was more psych-emotional and not in terms of energy-fatigue nor loss of belly fat. Some of the emotional lethargy and general head fog cleared up but I still felt physically miserable and tired all the time.
After a while on CPAP therapy getting quality sleep, a whole bunch more head fog went away and I feel like a new person. The T therapy was helpful enough that I continue on the med, and we're going to monitor if the CPAP therapy makes meds no longer necessary. I also have high BP which could be helped by CPAP therapy. Both of these are long term watch items, anticipating whatever improves will occur very gradually. I'm still relatively early in therapy and hopeful for natural improvement.
I would encourage you to bring all the data you have collected with you (on hard copy printouts) to the primary care doctor appt. Then talk through what the doc thinks your data tells you, what it doesn't tell you, and explore with your doc what you can get out of each type of sleep study. Doc knows best, all I would say is bring all the data you can so s/he can make the best informed recommendation on next steps for you.
As for costs, realize that T therapy ain't cheap either. Depending on your insurance two months of T therapy can cost you the same as the $900 lab sleep study. Brand T-Gel goes for about $480 a month (there is no generic). That is reduced by whatever your insurance will cover. Also, whatever T prescription you get look for a manufacturer coupon which can save you a hundred real dollars a month on the med.
But bottom line is you could go through 6-9 months (90 days, tweak dose, 90 days, rinse repeat) before you know if the T therapy is not effective. I guess if it nails your problem you will probably know sooner, but if it doesn't fix you it takes a lot longer to rule it out.
It's a tough call, maybe you aren't desperate enough yet to make the decision in favor of sleep study. For me I had exhausted many other diagnostic paths and I would have had the sleep study if I had to go collect pop bottles to pay for it. I believe the year or so of impairment has cost me far more more in terms of job performance, salary, and lost opportunities than the sleep test did, not to mention eliminating serious long term health risks of undiagnosed apnea.
Fortunately for me, it turned out to be a life changing decision to have the test, and now 90 days into CPAP therapy I am so much better off because I did it.
So I am biased toward doing the sleep study, and doing it in the lab.
good luck to you and I hope all of our perspectives shared on this forum are helpful to your decision process.
p.s. if you do pursue the sleep study and if you are diagnosed with sleep apnea, be sure to come back here and get read in about CPAP technology before you take your prescription to a Durable Medical Equipment (DME) provider.