How can I stop my iPhone from syncing activities to my iPad?

i was on my ipad and noticed there was an iphone icon on safari. i thought it was weird since i already turned off icloud from syncing on my phone. i checked it out, and it showed my moms instagram. its super strange because i looked at her instagram through my phone on the app. again, while i was scrolling through reels on my phone. i saw that phone icon again i clicked on it and saw the reel i was watching from my phone. im kinda getting scared. am i hacked or something?? or is it a glitch??? i havent updated my phone yet. someone, pls tell me if you're also experiencing this 😭

[Re-Titled by Moderator]

Original Title: my phone is keep transferring my actives onto my ipad