Man, if you really value your privacy you shouldn't use WhatsApp (difficult of course as everyone uses it)

and social media (difficult as everyone use it), except for Lemmy, Mastodon or Signal !!

Privacy is not an easy path as it's against the whole mainstream society.

But its worth embracing, because it's a human right, even if it's not "comfortable" doing so.

Edit: there is of course other ways of communication like regular phone calls or sending SMS instead of WhatsApp messages. So feel free to liberate yourself.

This might be the "Open by default" setting that is now per app in Android. Insta has "9 verified links" that will just open it instead of the default browser. Go to app settings, Instagram, Open by default, and uncheck Open supported links.

I don't want to sound like a broken record but Instagram is bad for privacy

Bro just uninstall whatsapp. Like idk what you expect ..

You can circumvent it using Intent intercept apps, so unless Whatsapp specifically looks for the APK and call it directly (and just use normal intent URL schemes) then you can simply redirect that request.