Letrozole with trigger VS IUI

I’m experiencing unexplained infertility. Have been on 2 cycles of letrozole which didn’t work. My RE recommends 2 more cycles on letrozole with trigger shots and if that doesn’t work then <a href="https://glowing.com/glow-fertility-program">IUI</a>.

What has been your experience? Should I directly try <a href="https://glowing.com/glow-fertility-program">IUI</a>? Too desperate!! TTC since 18 months and I’m 32+ yo.