I agree with you. Chelsea needs time to return to their best form, it won't be very easy and suddenly perform with their best again. Although they can perform well in some pre season matches, they may get some difficulties when they play against strong teams in EPL matches. There are many young players in Chelsea squad now, they need an adaptation. Moreover, there are many new players in the current Chelsea squad, their performance can be not really consistent enough when the new season begins.
Chelsea don't need time as an excuse anymore, we don't have the new coach excuse as well because this time around, we signed a manager very early and he has had the preseason with the team and had lead them to the premier league summer series title. Pochettino can do the same with the premier league and other league competitions. Chelsea has let go of many players that was holding the club back so for now we don't have any excuse and we have to let go of the excuse mentality and play football. Having young players in the team isn't something to be worried about because Chelsea used a young team to win the champions league and they can do that with the premier league.
Chelsea squad adoption can be done while they're playing and winning games. The squad is well balance and other players will be coming in before the transfer markets ends. Chelsea need an immediate response to make clubs know they should be scared of them and by winning Liverpool at the start of the season is a good step to follow. The premier league title race is opened to everyone and each clubs needs to be determine to make use to the last game to win it. Pochettino is doing a good job and by the start of the season, they'll be ready to entertained victors.