This is a list of providers who generally will provide letters with a single visit, though you may need to pay cash: https://dosomethingidentities.org/providers
Note that most of us require a lot more than 2 since they expire and wait lists are long. And you may want to verify if the insurance still follows WPATH from just a few years ago or from decades ago. Current recommendations are just one letter, but we all know most insurance still requires 2. And old ones sometimes required different combinations of providers with and without history with the patient or different levels of education. Also, it's all just gate-keeping, so don't feel bad about cheating, since they aren't even bothering to pretend it's for medical reasons.
I needed 6 letters personally. 2 to start HRT which as an agender person shouldn't have even been required even under current versions of WPATH, and wasn't originally part of my plan, but insurance, not doctors, insisted on, and I was required to be on for a year minimum. (But turned out I actually have enjoyed the breast growth I was a little afraid of, so for me it worked out, but other non-binary people it's forcing not medically recommended or wanted transitioning on them, the exact thing conservatives say WPATH is there to prevent). 2 more to get a consultation scheduled since the first two were expired by the time I got through that wait lists after the required referral from the HRT prescriber. And another 2 for the surgery date because the second two were too close to expiring for them (though not yet expired).
And for the first 2 rounds I had been on wait lists for both psychiatrists and therapists due to severe shortages in my area, so I would have been delayed another year or more if I didn't have this list (in it's previous form as a Google Sheet spreadsheet).
Just had my surgery last month. Now I have regular providers to do letters for the next surgery or revision surgery if needed since all of that will require totally separate letters for both consult and years later surgery dates after wait lists with the different specific surgery mentioned. US healthcare system sucks... ๐ตโ๐ซ