What about iOS to Android? My FIL wants to change his phone and it is iPhone and he is planning android.
You're in luck if you have a Samsung with Android 10+. You just need a lightning to USB C (or lightning cable + OTG) to hook up the iPhone to your Samsung; Samsung Smart Switch should detect the iPhone and help you get your Whatsapp setup.
Android 12 supports Whatsapp transfer as well, I believe you need a phone that comes out of the box with Android 12. Factory reset and follow the restore instructions. You'll need a lightning to C-type cable/lightning+ OTG to hook it up again.
For any other Android, unfortunately, you'd have to find one of the above 2 options temporarily, load whatsapp, back it up to G-drive and then load it again on the new device.
Video for reference for iPhone to Samsung:
(Hindi, couldn't bother to find an English video)
Video reference for iPhone to Android 12 smartphone:
(Telegu, couldn't be bothered to find an English tutorial haha)
Alternatively, you can purchase those apps that exist for doing this. They do have a high probability of success, but there's always a slight chance of it not working.
Cheers.