No, Arsenal last season was started quite good and they achieved many points, the mistake was happen in the near end of the season and Manchester City able to overtake Arsenal's position. Arsenal was only sign few players and most of their players are veteran, so there was no big change and they will with the same strategy.
While Chelsea, pretty much like a new club who has new coach and new players.
Yes, Arsenal at the start of the season were always consistent with every match, they got lots of points and were on track to win by seizing the moment and not wasting it, especially since they only focused on the EPL because they didn't qualify for the UCL last season so they were more consistent than several other big clubs, but Unfortunately Manchester City played well at the end of the season while Arsenal didn't, so Arsenal had to give up Manchester City getting the EPL title last season.
BTW talking about Chelsea as we know that it is not easy to revive a club that has been sleeping for a long time so it is difficult for the new coach Pochettino to set the right strategy for Chelsea's main squad, but besides that their management is also bad, too much spending is big but it is not commensurate with the results, Many players don't make a good contribution, but it's still early in the season, it's best to see Chelsea's development over time, this is a tough task for Pochettino for sure and give him time to show that Chelsea can successfully recover from adversity.