Confused with open world level system

*currently plan to have just 1 character.
**average gear score is 467

  • I’ve reached lvl30 in open world. Started to one-shot everyone.
  • Went to Chromie to switch to Dragonflight. Finished this campaign. Became lvl70. Enemies felt alright.
  • Decided to go after expansions in chronological order, starting with Burning Crusade.
  • Visited Zidormi in Blasted Lands, in the Eastern Kingdoms. She moved me back in time.
  • Went to Outland.
  • Found out I one-shot enemies and this campaign is not what I would like to do now.
  • Went back to Orgrimmar.
  • Here, I one-shot everyone too.
  • Went back to Zidormi to change timeline - nothing has changed, I still one-shot.
  • Went back to Dragon Isles. I didn’t do anything after Dragonflight campaign.
  • Turns out I almost one-shot everyone here too.

Questions are:

  1. Where did I mess up with level scale system?
  2. If I start new expansion (one of recent ones), will there be an NPC who can match world’s level to mine?

I answered your other post, which pretty much also answers this one. Best to discuss it further there.