I have changed a month ago because I had a good offer for a new Pixel 9. My iPhone XR was still running solid after six years and had good battery, but the battery wouldn't get better in near future and there is no more full system updates for that device.
I know what you mean, the integration of calendar, mail, passwords, wallet was wonderful on iOS, i truly miss that a little.
But I helped myself through migrating my passwords to Proton pass-you can do that, but until now you need a desktop PC, what makes it as of yet no solution for people who only have phones and/or tablets.
Proton Pass works really good most times on Android. I also use their calendar app, which syncs on all platforms, same as the passwords.
For cloud things (which I only use to transfer files between devices or when I need something stored for longer) i use a German cloud service from German Telekom, but Proton has a cloud service too. But like I said, i don't use cloud services much, so probably any will do.
With that concept I don't miss my iPhone much and can use my GrapheneOS smartphone together with my iPad and the mentioned apps let me have almost the same experience.
My reason to switch was that I can't afford a new iPhone, even the basic one is too much for what I want and can spend on a phone. And I switched to Graphene because I don't want AI on my phone as long as I can prevent it, and whilst Apple allows you to turn it off or generally has it run on device only, stock android doesn't offer this.
The security of Graphene and the fast updates is more a bonus to me, I have a very low threat model close to zero, i really just do ordinary stuff that you need to use nowadays.