Trusting Signal and/or WhatsApp and/or Android (google) and/or iOS (apple) with your precious photos, videos, and chats is a huge mistake.
All the photos, videos and chat history on my mother’s phone are now completely inaccessible to us, despite having recent backups and all the necessary keys and passphrases.
Can I transfer Signal backups directly from android to iphone? No.
Can I make a backup file and transfer that wirelessly without uploading it to the cloud? No.
Can I transfer it using a USB cable? Also no.
If I transfer it using the cloud, can I then restore from it on the iphone? … No.
It is not possible to transfer Signal chat history and media from an android phone to an iphone.
What about Whatsapp?
Can I transfer Whatsapp backups directly from android to iphone? No.
Can I make a backup file and transfer that? No.
Can I back up to google drive and use that? No.
Even if I could get the backup file, would I be able to import it on the iphone? Also no.
It is not possible to transfer WhatsApp chat history and media from an android phone to an iphone.
The entire ecosystem is sick
Signal is to blame: they do not make it possible to import backup data on iphone. They do not offer tools for working with backup data.
WhatsApp is to blame: they do not make it possible to retrieve or work with android backup data. They do not make it possible to migrate data from android to ios without fully wiping and resetting the iphone (and it didn’t work even when we did fully wipe it).
Apple is to blame: there is no way to transfer files from android without going through the cloud. Even using a usb cable doesn’t work.
Google is to blame: there is no way to transfer files to iphone without going through the cloud. There is no way to access a whatsapp backup blob in google drive containing my own data.
We all are to blame: we have accepted and continue to make excuses for an industry that acts in such a user-hostile way.