Oof sorry you're in this position.
I think endo and gynae treatment can become quite fixated around conceiving (which totally fair enough as that is overriding aim for some ) but it isn't the only issue.
I asked about the type of scan because ultrasounds are basically not a reliable method of identifying endo - they might identify it / they might not. As an example, I had an US that showed literally nothing. They did a laparoscopy and found stage IV endo,across bladder, bowel, both ovaries, everywhere. The pouch of Douglas was 'obliterated' according to summary afterwards. So, US isn't the final word.
MRI is much more reliable and can obviously be done non invasively.
In terms of symptoms, I had bad endo in PoD - and recent MRI showed more problems In that area. I also have endo around ovaries and adenymosis. Sex is and always has been painful for me - it's shit and it makes me very reticent about the whole thing tbh. It's painful while DTD but also afterwards.
Conceiving has also been v difficult. I have had a lot of gynae surgery and emergency surgery post birth so there's a lot of adhesions and scar tissue etc. having said that my first and only hard won child was conceived c 10 weeks after big endo surgery (yea it was OUCH!!) so I do believe excision and ablation made it possible for me to conceive.
Sorry that's a rather gloomy picture. I suspect / it looks like the gynae has taken the conceiving as the main issue and give you advice based on that. I don't know if you can, but you could ask for a referral to a different endo team (there are ones that are accredited within the NHS ) and seek an MRI. As for treatment, hormones (out if you ar TTC), laparoscopy and excision / ablation (might help/might not), and pain relief (might work, obvious side effects).
As for ovulation tests.. well I hope they work! As that's what I'm relying on. I do remember a GP telling me they were worthless though so who knows.