I'm not a WhatsApp user because Facebook, but it's pretty huge for some people. I was migrating some relatives over to iPhone who had lots of years of history here, and this was nearly a deal breaker.
WhatsApp itself CANNOT DO IT - your message history is all stored on your device. The only way to do it is with dodgy 3rd party software which started installing viruses on my desktop as well.
So yeah, anyway, think about the apps you care about and research them.
I believe if you backup to the cloud you can download your whatsapp back into an iphone
WARNING: FB + Whatsapp is a toxic company that violates privacy and tracks people. uploading to the cloud breaks the encryption AKA the cloud service can read everything and keep a copy of it, and possibly Whatsapp/FB too.
What does that have to do with money (and thus, greed)? The goal of every company is to grow. There's never a point where a company wants to stop growing.
There is a limit to greed. Coca-Cola can't possibly aim (although they wish) that every human on earth will not drink anything other Coca cola.
If Apple wants to expand there are other markets where they have a lower percentage like Macs, office software, routeres (which people keep asking to bring back). Truth is they know iphone is their gold laying goose and they want to lock them in their App Store that apple generates a cut from for being the gate keeper.
I am not against the business model but I see other areas where they can generate money instead of forcing everyone on earth to use an iphone.
I wouldn’t be averse to iOS and android swapping market share.
I am an Apple fanboy but there is a couple of things to consider:-
1) Having a mono-dou-oligo-poly is not in the interest of the general public. Its just too much power in the hand of one. Literally planet earth is work its life based on iOS. You can only expect the damage that will happen if Apple rolled out a flawed iOS version or just stopped working completely (same goes to google, microsoft windows, etc) . I just do not like one company having too much control.
2) The recent CSAM and other data collection method I am very wary of. We really do need more competition and stricter privacy regulations. One of the things that bothers me most that now most OS platforms you have to sign in to an online account to let you use the device. I assure you that you did not have to sign in into an account with OS9, Windows XP, or Nokia phones to be able to use it. Something is fishy here.