What kind of frustrations do you have on iOS. Since you've used Pixels, you probably are in a good position to compare.

The notifications are the biggest one. iOS insists on this Banner -> Lock Screen -> Notification Center lifecycle, and it drives me crazy that notifications move from Lock Screen to Notification Center simply by unlocking the phone and then doesn't show Notification Center notifications at a glance. I've missed so many notifications that way, because I quickly unlocked my phone to deal with something, thereby dismissing my current Lock Screen notifications, and then failing to realize that I had some, because when I tap my screen to light it up they don't show up (you have to explicitly swipe up to reveal Notification Center). Beyond that, I really appreciated Android's little top bar that shows the app icons that had notifications so I could quickly see if it was Slack, email, etc, that I had. Finally, Android lets you opt out of "Marketing" notifications at an OS level, while iOS doesn't have that.

Beyond that, I get frequent spam SMS's which are stupid. Android blocks all those. I have a Junk mail folder in email and hardly get email spam anymore. It feels like going back 20 years getting these random spam SMS's.

Finally, "glanceability" doesn't seem as good with the iPhone. One silly little thing is that if I'm using my iPhone it's sometimes very hard to see the date! If you have notifications you have to swipe down quite a bit to reveal that.