TikTok is like that but it’s loading videos continuously so it makes more sense that it would use a lot. I never noticed significant battery drain with Apollo.
There was a post on the mildlyinfuriating sub where someone had tiktok installed but hadn't loaded it in like a month or something, but it had used a full 2GB of data. Tiktok does more than load videos.
I always force quit it after I’m done. I wonder if that prevents this. Probably not.
Almost certainly not. I think if an app gets the right permissions on installation, it doesn't have to be officially running to take data and send it to the company.
Try out Reddit on a mobile browser. It's somehow less clunky than the official app, which is embarrassing.
Maybe consider using redreader instead
Maybe consider using Firefox for browsing the site instead. The UX can’t get much worse than it already is with the official mobile app. Actually, Firefox won’t be doing sneaky background stuff while you’re not using the site, so the UX should be better in that regard.