Not saying some companies aren’t up to no-good. But, collecting timezone (or ip to infer timezone), as long as it’s done with user consent in the privacy policy and or notifications setup process is actually helpful for end users. Most of us want (for example) our exercise reminder or our news update to arrive at breakfast even when we travel across Timezone boundaries. I don’t want to have to sign in to an app or go to a settings page for an app to tell it when I cross Timezone boundaries. If apps are collecting info to allow inferring Timezone without user consent then thats a different kettle of fish.
Not that I ever want linked in notifications, I definitely don’t want linked in notifications at 3am in the morning because I crossed a few international date lines.