Basically we had 2 rounds of ICSI in 2021 with my partner's sperm which didn't work and I struggled with the treatment (I got OHSS, which was actually the clinic's fault the second time round for not reviewing and changing my meds as they should have... but that's another story!)
Anyway, because I'd had such a difficult time with ICSI and it was so unlikely to work (it was like a 2-4% chance with my partner's sperm), we decided it would be best to just come to terms with using a donor and not put me through that again. So we did all the emotional work etc of coming to terms with that, joined donor conception network, went to all the events, did the research, etc.
My partner also has a health condition (which is the cause of his infertility) - and it may or may not be something that could be passed to a potential child, we don't know. It just seemed better all around to use a donor.
We then started private IUI (because I was fertile so no reason to think it wouldn't work) - we did 9 rounds because I'd found IVF so difficult and really didn't want to go back to it after the OHSS. We knew the chances of IUI working were only about 8-10% each month, but like you I was scared of the IVF, so we just kept doing it.
After trying with that for about a year, we were told we'd now be entitled to another round of IVF on the NHS (the funding had changed from 2 to 3 rounds in our area), so we went onto a waiting list (for a year!) for that.
After waiting a year, we were told that they wouldn't fund it if we used a donor - even though we already had the sperm in storage - because it was 'our choice' to use a donor. There was a 2-4% chance that ICSI would work with my partner's sperm so they wanted us to go through that again. By this point I was in my mid-30's and my partner in his mid-40's.
Honestly - I was so angry at that point, being left on a waiting list for a whole year only to be told no, I just couldn't stand the idea of continuing treatment at that clinic. They'd also made other mistakes and we were both feeling pretty resentful and traumatised by the whole thing.
So we switched to a private clinic in London on the recommendation of a friend, who were absolutely amazing.
I did IVF with donor sperm late last year. I didn't have any bad reactions at all, no OHSS (because they put me on the right medication!), it was very easy and smooth. I got pregnant with the very first embryo transfer.
I'm absolutely gobsmacked still, that I got pregnant so quickly after all this time and pain.
So I would say - yes, go for IVF/ ICSI - it will be fine - but do choose your clinic carefully!