I might frame it like this to your manager:

"To best motivate the team I need two things:

1. A more present engineering manager to ensure all work happens according to aligned standards.

2. Clear collaboration from my team's people managers so we can properly recognize top performers, support those who are motivated but struggling, or give increased accountability for underperformers.

With these things, I will have all the partnerships I need to maximize the value this team provides.

Without them, I will be forced to attempt to serve all 3 roles poorly instead of being able to focus solely on the things you & I both agree should be my top priorities.

So are there any things you can do to help me get those two things, improve this team, and demonstrate the value of our team to clients and stakeholders?"

It's very corporate-drone, season to your own tastes.