Okay here goes!
I am not an expert on endo. I have been told I have some scarring from adenomyosis (which was clearly never diagnosed when I was young and had bad period pain.) Having used HRT for 12+ years it's not made it any worse.
My understanding is that it's estrogen that fuels endo/ adeno as it makes the tissue grow. Progesterone stops the 'proliferation' , as it's called.
I am not aware of any difference in the pain/bleeding with endo according to the type of progesterone used ( either synthetic progestins or body-identical micronised progesterone.) There may be, but logically I can't see how as it's estrogen that makes the endo grow.
I have never heard of any type of progesterone causing estrogen 'surges' because- for example- women on the mini pill (progesterone only) don't get that and they tend not to ovulate either.
I would guess that with endo, the more progesterone you take, the better, as it will reduce the growth of endo in your body (fuelled by estrogen) so that would mean taking continuous HRT which is a daily dose of estrogen and progesterone. Please bear in mind I am simply suggesting stuff and am not medical!
If you were to go for a continuous regime, the gold standard at the moment is estrogen as a patch or gel, plus daily micronised progesterone 100mgs.
A lot depends on if you have pain when you bleed, and a continuous regime would avoid a monthly bleed.
I'm a bit surprised you have only been given progesterone and testo as testo is never usually prescribed without estrogen. Most women using it start a few months after they have had their estrogen dose sorted and feel the need for something else too.
(Can you PM me the private clinic as I do have some ideas about which are good and not so good.)