Afraid of someone restoring my photos or videos after erasing

Hi

3 or 4 years ago I sold my iPad 2 after selecting Factory reset or Erase all content options

Problem is after finding out that photos and videos can be restored from any iOs device I started to get afraid

I had alot of personal photos and videos in my iPad 2 and I'm afraid that someone will be able to restore everything I had in my iPad 2

I didn't do iTunes or iCloud backup at all I just did a factory reset and sold the ipad...

Please make me relax my heart is beating fast and i cant stop thinking