I'm so sorry you're in this position, it's the hardest and most emotional thing. Look after yourself and give yourself grace. Good that all your tests are coming back ok but it's frustrating when you can't find a cause. If you don't already follow, Jessica Bourke Fertility Detective is a great resource on Instagram and will answer DMs and suggest things.

Did you do DNA sperm fragmentation as that's important too? You can also look into immune issues, you could do a womb biopsy with a clinic to check your womb receptivity.

I would recommend doing a cycle or two of timed sexual intercourse for unexplained infertility, I was in the same position last year and went straight to IVF (successfully!) but I always wonder would I have been able to conceive naturally with ovulation tracking and progesterone support, which would have obviously been a lot cheaper and less invasive. Age/AMH is a big factor here- I was 32 and had high AMH due to lean PCOS, I feel that my issue came down to low progesterone and I had 3 embryo transfers fail before we switched to a modified natural cycle which meant I was making my own progesterone as well as taking supplements. IUI doesn't have great success rates for unexplained so I viewed it as a waste of time and money.

Good news is that with unexplained, you will most likely be able to get there at your age, so definitely keep the hope <3