I was lucky not to have to make these choices for myself, so being unemotionally involved and having no personal biases, I'd look at those odds and jump to IVF.
Anecdote: I went from being told that I had no eggs, couldn't have biological children, to being recommended a Hail Mary IVF after surgery for fibroids, cysts and endo. Ironically, my grandmother had just left me just enough money in her will at the time to cover the IVF.
We got seven eggs, four fertilized and only two worth transferring, nothing to freeze.
I was given 30% chance of success. We had twins.
With the odds they're giving you, I would absolutely go for it!
Definitely IVF with ICSI. My injectable IUI cycle had pretty much the same amount of meds, blood draws, ultrasounds etc as my fresh IVF except there was less control over the outcome so I always point out to people weighing the decision that IUIs are not "easier." Especially with sperm issues ICSI gives you more control over the process. Hopefully you won't even need frosties but they are nice to have.
I would do IVF. If you're a good candidate for another IUI now, you'll still be a good candidate if IVF isn't successful. But hopefully another IUI won't be necessary.