Welcome to AC!
Before assuming someone tampered with your phone, it’s usually best to rule out the common causes first — software glitches, synced accounts, backups, or apps restoring old settings.
A few things you can try:
1. Make sure the new phone wasn’t restored from an old backup. If it was, the same settings, apps, or issues will carry over automatically.
2. Change passwords from a trusted computer — email, Apple/Google account, social media, everything.
3. Check which devices are signed into your account (Google/Samsung have a “devices” page). Remove anything you don’t recognize.
4. Factory reset the phone and set it up as new — don’t restore anything.
5. Avoid installing random apps, especially ones outside the official store.
If you can share what “same stuff” is happening, someone might be able to help figure out if it’s just settings syncing or something else. Most of the time it ends up being an account issue rather than someone hacking the phone.