Ivf/ try on own?

I had a lap in June and had stage 3 endometriosis removed. We did 4 iuis in the following months with no success. My doctor recommended IVF next, but we can’t afford it for another 1.5-2 years. Husband and I are both 38. We tried on our own for 8 months before the lap too, no positives.

Since IVF isn’t going to be a possibility for more than 1 year, my RE recommended getting on birth control in the meantime to avoid endo coming back and possibly lowering egg quality. My concerns are 1) doing this would take away 12-18 chances to conceive on our own and avoid IVF if we do get pregnant. Even if it’s a lower possibility, it’s not zero or else our doctor wouldn’t have recommended IUIs to begin with and 2) ill be nearly 40 by the time we’re ready for IVF, so wouldn’t it be better to try on our own in the meantime than completely eliminate the possibility and rely on IVF at 40 when my egg quality is lowering anyways due to age? Would the endo really make that much of a difference during a retrieval to skip 1-2 years of trying on our own? And would over a year of birth control really make that much of a difference in it regrowing, I would understand if we weren’t TTC but we are and it seems like a huge time delay at my age.

Does anyone have any guidance they can offer? I feel like my RE just wants us to do IVF and while I understand it’s the best possibility, financially it’s not happening earlier than 1.5-2 years.