Could you please check?
Hi! I'm sorry I don't remember your name, you had an interview today and I entered the room in the middle of it. I'm not sure if you remember me. Anyway, I think I can relate to your frustration, at least to some extent. Since I've been through this process a lot, I mean interviews, I might be able to help you with some advice. Let me know if you're up for it.

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It’s very good and better than most native English speakers could write. So my only suggestion is a small one. The “, I mean interviews,“ is slightly awkward. I thought of a few other options, but this one is the most natural and simple:
Since I've been through the interview process a lot, I might be able to help you with some advice.

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looks good