Nope, going solely off the eye test. My conclusion is what you said;
Our offensive issues might be due to do two things:
The quality of our final couple of actions in attack (a personnel issue, ie Havertz plus injuries)
I think it's the above, more specifically, the reduced speed and accuracy of passing through the centre of the pitch in the first phase is having a cascading effect in the attack. Last season, we saw Zinchenko consistently passing vertically to Xhaka who then released Martinelli in advanced positions at the edge of the box. There was a similar pipeline in the right channel with Partey playing incisive vertical passes to Odegaard who released Saka in high advanced positions. We had a well oiled box midfield in moving the ball back to front.
What I'm seeing this season is fewer vertical passes in the left channel because Tomiyasu is sharing game time with Zinchenko, and he makes more lateral passes to Martinelli in deeper positions, rather than vertical passes to Havertz. Similarly, Rice and Jorginho aren't consistently playing vertical passes through to Odegaard either, rather having a tendency to play more lateral passes to Saka, who like Martinelli is also getting the ball deeper on the pitch.
That's what I'm seeing which is the team playing the ball less through the centre which requires more skill and bravery, and rather more lateral passing which is easier to execute and less dangerous. It's happening because of the reduced passing capabilities of the midfielders this season relative to last. Havertz, Rice, Jorginho and Tomiyasu aren't as good at passing the ball as those who played in their positions last season and its adversely impacting how quickly we move the ball forward and consequently how good our attack is.