Safari on mac automatically opens multiple tabs every time it launches - FIX!
Just in case anyone is having this issue I wanted to describe what worked for me. People suggested going to Safari > Settings > General and then New windows open with. That was not helping. They suggested deleting history. Didn't help. Suggested unsyncing iCloud. No luck.
Finally I figured out if you got to Safari > Settings > Profiles. Select the profile you are using (for me, it wasn't happening on my "personal" profile, but only on my "work" profiles). There's another option for "New windows open with". If you're having the same issue as me you'll see "Tabs for Work" selected. I changed it to "Start Page". Quit safari, relaunch, no more one billion tabs open!