Congrats. iOS has a native transfer option when you start setting up the phone - that's the easiest way.
Google services work well on iOS, except Assistant (which is not default, but can be assigned to a widget). I'm pretty much on the same boat, and primarily on Google services.
Be warned - basic iCloud account is 5gb, and with WhatsApp and full phone backup, it'll quickly annoy you in the settings app to upgrade. The Apple one plan comes with 50gb and other stuff, and is decently priced, and many perks can be shared with family IDs too.