So far we have only seen Arsenal beat Man United, the quality and depth of Arteta squad will be truly tested when they meet Man City, Liverpool, Chelsea and Tottenham. If you can secure points at the meeting with these clubs, Asenal will really end their title drought at the end of the season. Yesterday's win at home from United deserves appreciation, but we know this is just the start of the season.
On the other hand, Man United is still unstable, even though Ten Hag has spent a lot of money in the transfer market. I see United fate almost the same as Chelsea fate at this time, not yet completely stable.
Arsenal won Manchesger United with full pressing dominance coming in from gunners. However they have priorities to meet up this season, perhaps it's still early and we're waiting to witnessed more to come. Arsenal are promising this season, they have good chances of winning more elite encounters this season. Mikel Arteta is having a good time as manager for Gunners in the ongoing campaign. Whatever accolades he's accumulating, he deserved them without hesitation. He keep building the club for the past years and seems now is the time for him to start reaping were he sowed.
Arsenal won against Manchester United with a very good performance that shows how improved and prepared they are this season since they are able to win their matches convincely but until we see them do better at the middle of the season or before the end of the season I don't think they are to be praised yet knowing that they can play even 5 matches without getting a positive results. Arsenal's performance looks promising as you said but let's remember last season when they were unbeaten in more than 6 matches but when everyone expected them to utilize the opportunity to win the English Premier League they allowed the trophy slip out of their hands I don't think they will forget that in a hurry.
For them coach Arteta I think he's got the experience, learnt his lessons and ready to keep improving the quality players he's got in the team but until they get to face and win Manchester City, Liverpool and Tottenham Hotspur we shouldn't take them seriously yet or see them as league contenders with City.