(Context: I've constantly put off looking for a job for various reasons. Since I want to make the tens of thousands of dollars I paid for my masters worth it, I had the thought to speak to a career coach to overcome my anxiety around it, before I finish my masters and go into full panic mode. This is my response to one of the coach's questions.)
For interviews, I've thought of another frame, which is that of an entrepreneur selling a product. This is another frame I'm deeply unfamiliar with, though I think it's the most appropriate. If I go into an interview with the frame of, I have to prove myself, it starts with the assumption that I should be given an offer, and any deviation from that is a failure. It's a test-taking mentality. Whereas, if I'm an entrepreneur selling a product, there's no such assumption. A product might not be ready for market, or it may be ill matched to the potential buyer, or any number of other factors. It also highlights that my lack of confidence in interviewing might not be appropriate to the current circumstances. A brand new graduate is a commodity, by now I'm a specialised product. Nor can the product be easily changed to fit potential buyers; fit comes from matching with suitable buyers, not short-sightedly changing the product for every potential buyer. It's also possible to be open about a product's flaws, as long as the overall benefit outweighs the cost.
The reason I'm not used to this frame is because I'm used to friendly environments. In school and at work the people around me in theory all have the same goal. Entrepreneurship is a different beast, and I have to make friends of strangers with different goals. But I see myself as an entrepreneur, in business or otherwise, so I have to figure out how to do this eventually. I already have a decent grasp of getting along with people in friendly environments, and I think it makes sense to start reaching my grasp further.
The other mental barrier I have with interviews is I think I "deserve" certain jobs I'm not confident I can get. But from an entrepreneurship perspective, this is incredibly silly, akin to the Ivy League daydreamer who wants to start the next Twitter. Entrepreneurship is inherently "dirty", where the founder has to do all the random menial things needed to keep the company running. This doesn't mean aiming so low I hit the ground, but it tells me I should shop around for offers, and take the best I can get (assuming it passes some bar to make the offer positive-value), even if it's "beneath" me. On a practical level though, I think it might be wise for me to avoid "Ivy league" companies for now. Regardless of how I frame it, I suspect a rejection will lower my confidence, and confidence is a resource to be managed carefully. A 10% chance of successfully getting an "Ivy league" job is probably not worth it.
The point you mentioned about being "open-minded" applies. It's easy to assume that if there's top-tier companies, everything else is bottom-tier, but that's too static of a picture. Yes, at the bottom layer there are companies that failed to be top-tier, but there are also companies who are yet to become top-tier and are in the process of doing so. At this second layer I have the impression that there is a talent crunch, since prestige-chasing talent is being sucked up by top-tier companies, so there is an opportunity there. I have this impression because of a retrospective by Matt Yglesias, one of the founders of Vox. He mentions that at no point did he feel a doubling or tripling of investor funds would lead to a rapid scaling up of talented writers. Nor is it obvious that more prestigious companies would be able to give me better growth. The metaphor I've read for the effects of scale is, large scale industrial agriculture maximises output per unit labour; one labourer with a combine tractor can harvest many acres of land. But small scale agriculture is more efficient per unit land, akin to a lovingly tended garden optimally packed with diverse plants.