We regularly see this question and we get the same types of answers. I'd like to offer an unpopular take and echo Jonathan Blow's sentiments [1] on the topic: if you feel like an imposter, then you probably are an imposter. So you have a responsibility (or several) where you lack either ability or understanding, or both. It sounds like you know what you should do: improve your ability and understanding for what you are responsible for, either before the bureaucracy finds you out, or before you hurt someone.
Mid-senior level, so I guess you're about 75 years old? JK. I'm not sure what that means in context, but here are some tips for impostor syndrome in general:
1. Re-label it as many ways as you can. Write down when and how it shows up for you, and use that information to describe the term using different words (i.e. don't use "impostor" or "syndrome"). This can sometimes automatically suggest new ways to tackle the problem.
2. Note its comings and goings. When is it most severe? When is it less noticeable? These questions can help you to understand more about yourself and find new ways of getting control over it.
3. Expectations management through objectivity: Write down what you expect of yourself, in the most optimistic case. Then ask others what is literally expected of you. Sometimes it's a good idea to reverse the challenge on yourself, for example if a C grade is minimally required, then aim for a C instead of an A.
Just some ideas from coaching people through such situations. Good luck.
I think it's common to experience this when taking on a significantly different role or being exposed to a new environment in your existing role (such as going to an industry conference for the first time). Your interactions with others are different than what you are used to and our brains are wired to bring that kind of novelty into sharp focus one way or another. It's an errant or exaggerated error signal.
Know that in time it will dissipate naturally as you gain experience and the new interactions become familiar. In the meantime don't let it affect your confidence in your work or others will pick up on that.
1. Consciously acknowledge it as a mental artifact and disregard it as such. Don't just ignore it but call it out in your mind as you feel it happening: "This is just imposter syndrome. I'm going to disregard those thoughts because it's not real and not helpful."
2. Strive for excellence in what you do.
3. Derive and project confidence from following step 2.
Whenever I have a crisis of confidence at work I remember the time I overheard being labeled an ‘Idiot Savant’ and just accept they keep me around for some reason I’ll never fathom.
Does feeling like doing what your job/manager asks you to do won't actually be good for their corporate goals make you an imposter? Kind of feels like being a fraud to me and I feel like that's something I worry about more than not deserving technical respect. Might as well work in sales and directly lie to people.
Or worse, finding out that what you do is good for the corporate profit motive but bad for humanity?
Getting what looks like a good job and then when you arrive finding out that you're just being paid with monopoly profits to find new ways of locking customers in, thwarting competition and extracting involuntary customers hard earned wages from real actual work with dark patterns.
Compared with that even getting paid to work on some middle managers pet project that will get canned and forgotten the second he jumps to a new org is probably a positive.
I was talking to some old shipyard workers last week, welders. When they were skiving off they used to carry a construction plan with them. They did this as their gaffers, their bosses wouldn't challenge them. The gaffers didn't know how to read plans.
Everyone thinks there is genius further up the ladder. Sometimes there is but mostly there is not. Stop beating yourself up. If others have a problem with your work they will let you know I'm sure.
[1] https://youtu.be/YUFXuxa0Drk?t=89