I agree with your opinion about Chelsea. They are one of the most serious contenders of the Premier League title at the moment. It wouldn't be the right thing to overlook them this season. I can still say that they need some transfers now on one hand. For example their biggest need is a striker now as Lukaku is no more here and Werner might also leave the team soon. If they somehow find the right striker for themselves then they would really compete harder to achieve the title.
At least during the pre-season friendly matches they looked kinda bad tbh. They didn't look like a team in itself and just individual players trying to put in a shift. Watch them against Arsenal and they were completely outclassed by Arsenal's play. They need better team cohesion and team play, which is the managers job to sort out. Yes, they do lack the quality up front as I don't think Tuchel rates Werner highly as their main man up front. Chelsea really needs to get busy in the transfer market. All their transfer prospects seem to be joining other clubs from the looks of it. With Prem starting in a week's time. They should seal the deal for a quality striker soon. So that he's up and running in a few weeks.