Ten hag wasn't in a tough league, and secondly he was in the toughest club ruling a weak league for that he had better advantages. I will support it if u said Ten Hag is more experienced than Xavi but saying that he is a better coach than Xavi I will say u judge based on the current performance. Becaquse the same reason should make u rate him above Artetta but because Arteta is doing well, u wouldn't say Ten hag is better than him.
A very good review about Erik ten Hag surely he was in weak league with tough team which give him some good advantages and his experiments are also working in English Premier League as well which are helping him for having better results against opponents even he is still looking for better results and time will tell how good he is with Xavi he was relatively new and have no good experience but good player, but his coaching ability is also good with he started from poor and now having at the top of Spanish league.
Arteta is completely different person he is here for sometime with good support and hard work he achieves good results if Erik ten Hag able to do same thing then surely we can compare him with Arteta because then surely this could be comparable, but Xavi is totally in different peace of mind.