Struggling with Endometriosis Diagnosis and Pain Management

For those in the UK under the NHS, how did you go about being diagnosed officially with endometriosis and having a laproscopy? I was diagnosed with PCOS at 16 and had opinions from multiple doctors that the issues I experience suggest endometriosis, but at the time due to covid and my age the gynecologist was unwilling to refer me for a laproscopy. I'm 20 years old now and after being told the problems would "just go away" within a few years I am struggling more than ever with the pain and exhaustion. Did a formal diagnosis help you with treatment or management options? Is it worth pursuing and if so how do I go about this? Its worth mentioning that due to my history of mental health it is very difficult for me to be prescribed the pain medication that I find effective, and as a result I have little to no pain management options. If anyone has effective pain management options that would also be greatly appreciated.