How to give constructive upward feedback towards an Engineering Manager?

What constructive feedback should be like is in the name: "Constructive". The goal is to help build up the other person to be better. The primary ingredient here is to suggest a course of action they can take to improve. I cover all of this in this section of my Effective Communication course: Effective Communication For Engineers: Giving Feedback

I actually recommend going through the entire course as it covers other tactics like using tentative language and empathy, which I believe apply here.

Here's another good video on the topic: The Hardest Part Of Peer Feedback: Giving Them Constructive Criticism

Also, will this feedback be delivered to your manager directly or to their manager and then anonymized? If it's the former, I would retool a lot of the language in your current points as it's pretty frank and could be delivered in a nicer ton. If it's the latter, then you don't need to worry too much and can just be honest.

Some specific items also stood out to me, so I'll comment on those:

2. My manager assigns stretch opportunities to help me develop in my career?
~ I don't really understand this question

I'm 90% sure a stretch opportunity is a big project that is currently 1 level above what you're currently operating at. So giving a senior-level project to a mid-level engineer is a classic example. These projects are crucial for promotion and building skills - You don't learn anything when you get a project where you know how to do 100% of it.

6. My manager gives me actionable feedback on a regular basis
~ Nope 1-1 is there is no feedback for me

Maybe you can give them clearer on ramps to give you feedback? Check out this video: This Is How You Get Feedback - Making The Process Smooth

8. My manager has the technical expertise required to effectively manage me.
~ Nope, they lack

I would elaborate on this - What technical skills do you think they can help you grow? Debugging? System design? Data analysis? The more specific you are with feedback, the more likely you are to get the response you want.

At a high-level, I would try putting yourself in your manager's shoes and envision getting this feedback. Would you be happy? Clear on how to improve? Confused? Once you do that mental exercise, then you will understand how to deliver feedback that is honest, actionable, and empathetic.

🤣 I swear I've answered these exact questions for my past Google managers!

Jokes aside, I just want to note that you seem generally dissatisfied w/ your manager, aside from the fact they seem to recognize your ability to contribute. I think most of us can empathize being managed by someone who lacks the capability to understand deeply our work.

My $0.02 is that you need to be clear with yourself about the outcome you want. Do you hope for your manager to genuinely listen to your feedback and get better? Or do you just want to vent (anonymously)?

There's nothing wrong with wanting to just vent - after all, you may believe that your manager doesn't want to and/or doesn't have the ability to change. I've encountered managers of both types and have genuinely attempted to give constructive feedback to help them. Neither got better. In this case, resist the urge to unload on them and just write something vague and leave it at that - if you don't really believe in your manager, then you probably should just leave and find someone else to work with.

But if you do believe your manager is open to feedback and is willing and capable of change, then write the feedback as honestly as possible without being hurtful, and include examples of situations in which you think they could've done a better job at.

In fact, I would recommend going one step further and offer your manager an opportunity to discuss your feedback directly, one-on-one. Doing so obviously require you to trust your manager and for your manager to trust that you genuinely want the best for them. But if your manager is indeed able to absorb your feedback and improve, this will not only improve you and your team's wellbeing, but also earn yourself an extremely valuable ally and advocate. As a newbie manager myself, I cannot be thankful enough to my reports who are brave enough to tell me the tough feedback face to face, as I'm fully aware of I've got a lot of room to improve as a manager.