I participated in the Premier Leagues voting on who will win the 2024/2025. With over 7,300 participants, Arsenal took the slight lead with 37% followed by Liverpool with 31%. The defending champ City at a distant third with 16%. I voted for Arsenal as well but not for a technical reason, I just thought that maybe they deserve it this time after coming close in previous seasons.
Meanwhile, in our forum voting (17 total votes), City has a commanding lead with 64+% over their rival Arsenal with 29+% 
I think if we all are allowed to revote, then maybe we might see something different. I believe the reason why you saw arsenal having a greater chance is probably because of the absence of Rodri. We all know how important Rodri is to the team, and how city sometimes struggle to win games without him, so if Rodri is going to be out for the season, then City's chance is likely to reduce.
And arsenal on the other hand already have some injury boost. White and Zinchenko are likely to resume this week, leaving only Odegaard on the Injury list, and we've seen some videos of Odegaard having some personal training, but his return date was probably delayed so reasonable purposes. Maybe it's just arsenal's season, who knows?.