Transition from floor tiles to outside at external door

There isn’t many options here due to the door threshold not being able to be adjusted for obvious reasons,
You can finish with a ramped bar along the edge where the door is but not ideal as it’s the front door. My personal suggestion would be to have a mattwell feature in front of the door which should leave no height issues then lay tiles up to the Matt with a finish edge around tiles.

Go to your local tile shop, like Topps Tiles or Tile Giant, explain what the challenge is, and they should be able to show you what are called, Transition Strips. (even better, take a close up pic along with you, and even one tile if you have one)