My situation is different from yours in that I had a hysterectomy as well as BSO at the time of endo surgery, but I don't get on with Utrogestan either (causes insomnia).
What I wanted to bring up is that, in ladies with a history of endometriosis, the recommendation (from BMS, ESHRE and others) is to have combined HRT since oestrogen only can cause the endo to grow back. I don't know how common it is, but certainly on the Endometriosis UK forum, there are ladies there who've had reoccurrence on oestrogen only following hysterectomy and BSO.
"For hysterectomised women with endometriosis it is advised that continuous combined HRT is started for at least the first few years after surgery. This may be changed later to estrogen alone due to a possible better safety profile in women over the age of natural menopause but this needs to be balanced with the theoretical risk of reactivation and malignant transformation of any residual endometriosis, which can occur many years later "
https://thebms.org.uk/wp-content/uploads/2020/04/10-BMS-TfC-Induced-Menopause-in-women-with-endometriosis-APR2020.pdf