Disclaimer: I am Android developer who uses iPhone and Mac for personal usage. I believe Apple's walled garden is much more private, much less distracting and pathetic; and - much less technically capable than Android. In fact Android on any given day will hit iOS out of the stadium when it comes to technical process. iOS is also much safer - just because it's a walled garden. Having said that - congratulation! You are on the right track. P10 is a fanstatic phone. Besides Apple at this point is intellectually and technically bankrupt - they are just selling because they have a captive hostage of a fan (!= customer) base (Though if I had to I'd have bought Pixel 9a or 10a; I hate gigantic phones and I hate camera bumps and too many cameras with everything I have in my bones).
Having said all that - I will try to give some suggestions (as I use both: Android for work and testing; and iPhone as my personal phone) for things that kinda are crucial:
Passwords -
https://bitwarden.com/help/import-from-safari. BitWarden essentially is the best password manager out there - even better than 1Password imho; Apple's doesn't even fit in the competition. So you are sorted. Look on their website and see if they have a better way to move out.
Photos: Yeah, Google Photos works fine. If you want privacy -
https://ente.io is fantastic. It's FOSS and very capable. I use it on my Mac and iPhone. Yes, just like BitWarden it's FOSS and multi-platform. Also if you have upto 20GB then it's free - after that it costs and it's very reasonably priced. (Whatever you pick - do the transfer/copy to [new solution] before migrating to Android - preferably on the Mac if you can)
Messaging: Yes, ensure you do this when you already have the iPhone preferably and install WhatsApp/Signal (or whatever if your poison in that geography) and let your people know you have moved; and start using RCS. It's not where it should be - but it's important we consumers push cross platform features.
Browser: Install Firefox on Mac and import whatever you want to into Firefox and setup sync - then enable sync on Android. You can do that for Chrome as well. Because even though I absolutely despise Chrome it's really cross platform.
Calendar/Reminder/Notes: For calendar Google Calendar is fine (there are lots of alternatives like
https://www.calendar.com, you can explore);
https://tasks.org is a great Reminders alt. There's Google Tasks and Keep that I haven't used in a long time. For notes as well there's Google's default one but moving to a great 3rd party notes app is highly recommended - Simplenote (as it says - very simple), Goodnotes, or Obsidian/Joplin (if you do serious note taking which if you did then you'd already be using it).
2FA (if you use/need): BitWarden paid (I don't need paid features but I pay just to support it) supports TOTP 2FA and also Passkeys but I use Ente Auth for TOTP 2FA because it's a standalone app and like everything Ente it's cross platform and yes FOSS. I don't want my passwords and 2FA in the same app.
Sync: If you have been using iCloud for file sync b/w iPhone-Mac then you need to use something else - like Dropbox, pCloud, Koofr, Tresorit (and more) - these are all cross-platform (and -
IMHO - at least, let's say, 100 times better than the opaque and incompetent mess iCloud suite is). Then there's also Google Drive (I don't use it but technically it's superior than iCloud but I hate its UI/UX;
PS. I hate anything by Google for the constant tracking/scanning it does - so that's there; oh, it's do that on your Android as well - so you will have to accept that).
Music: If you use Apple Music then use one of those "playlist transfer/sync" apps to sync your Apple Music data to something else e.g. Spotify, Youtube Music etc (because Apple Music is pathetic on Android; I've tried it).
Mail: Thunderbird is on Android (unless you use Gmail and Gmail apps then you are sorted already; I personally would use Thunderbird even if I used Gmail which I don't).
Health Data: Look at your Health/movement/training data if it's on iCloud/Apple suites. See how it moves and whether you want to move it. If you have been using something third party like Strava then you are set already.
Google Find Hub (I think your friends also need to use it which I suspect might be on iOS)
The thing is a lot will be transferred via this alone:
https://www.android.com/intl/en_in/switch-to-android/ (your apps, unless it's an Apple garden only app, will be moved as well - not sure about data in those apps from the iPhone - but certainly it will fetched on login). But I'd rather do moving to other services before the actual transfer to be safe.
tl;dr:
- Do whatever migration/copy/sync you can do before actual migration - preferably on the Mac, so you can control and verify better.
- Try to use cross-platform apps/services so that the next time you are moving, you don't have to think about it, i.e avoid lock-ins as much as possible.
- Also - since you are on Mac, a lot of data isn't going anywhere anyway so you can do it even slowly.
