I'm afraid you are mistaken, very mistaken.
Arteta went from 1,32 expected points per game his first season to 1,55 expected points per game in his second season (positive change of 0,23 expected points per game). And from negative 0,20 expected goal difference per game to positive 0,24 expected goal difference per game (positive change of 0,44 expected goal difference per game).
Arteta didn't take over a 5th place Arsenal, he took over an 11th placed Arsenal with a negative goal difference in free fall midseason. No pre season, just straight in to the tight Christmas program.
ETH's first season was good, his second season was a catastrophy.
ETH went from 1,74 expected points per game his first season to 1,17 expected points per game his second season (negative change of 0,57 expected points per game). And from a positive 0,57 expected goal difference per game to a negative 0,38 expected goal (negative change of 0,95 expected goal difference per game)
If you're not already the best team in the country, progress is the only valuable measuring stick. ETH has taken the team from a good season and has not just not made us better, but has made us mindblowingly worse since.
Klopp and Arteta showed clear progress all their first 3 seasons. ETH's negative trajectory is record breaking bad.
So no! ETH's first two seasons hasn't been better than Arteta's two seasons. ETH first two seasons has been a catastrophy because the current status is that we haven't been further away from the best teams in the country since Fergies early days in the 80's.