It's a good bet choice and I also plan to do the same, Now it's very difficult to predict who will win this game because both teams have improved for the better and I think the current strength of the two teams is not much different, Arsenal and Manchester City have competed been tight since last season and of course this time it will be too.
Arsenal have added several new players at this time and made this team much more solid, while Man City did not make many changes but Pep Guardiolaala's team is indeed strong enough despite being left behind by several key players, maybe that's why it makes it a little difficult for me to predicting who will win this match, and I think for the choice of betting on both teams to score I think it's very appropriate.
You seem to have a lot riding on the upcoming Community Shield championship match between the Cityzens and the Gunners. The conflict between Mikel Arteta and Pep Guardiola his former coach adds a fascinating layer. The odds point to a challenge for Arsenal but you have chosen a balanced strategy by placing a wager on both teams to score rather than merely the overall victor. Changes in dynamics and strategies will probably result from the influx of new signing and the departure of important players. Due to Arsenal steadfastness in breaking their pattern versus Man city this match may include surprise and intense competition.