Not saying I disagree with you though, I think identifying heavily with your job makes it even worse.
The fact that you are getting steady interviews speaks for itself that you have the design chops and experience. I think people don't know how to interview design candidates well as is, removing the physical cues you get from an in-person interview makes it even harder to assess a designer. Also, it could just be companies are flying by the seat of their pants and a lot have reduced workforce with this second wave of infections.
High probability it's not you, it's them and their broken process during covid-19. Keep your design skills sharp and keep building your portfolio and use this time to work on concepts that you are passionate about that haven't come up in a 9-5, that will help you until the right opportunity comes along. You got this!
My approach for take home challenges is this. Often I complete them and never even get any feedback from the firm beyond a form rejection letter. If that is going to be the case anyway I might as well make something I'm proud to have in my portfolio, even if it doesn't line up with exactly what they are asking for. That transforms the work from something that I'm doing for them to something I'm doing for me. I know that's hard when you are unemployed and have bills to pay, but if at the end of the day you have some work that at least meets with your expectations you can retain that bit of your pride.
When JS frameworks and SPAs took over the web, he adapted himself. But being a UI engineer he cares about the craft's visual aspects, than the technicalities of JS.
Although he has a proven record of his works, he is now dealing with interview questions like "what are the problems with closures" and "when you do use function.apply()" and "immutability".
I already know where my strengths and weaknesses are. I'm fine with 1 on 1s and all that, but when it comes to the technical part of the interview process like a take-home design project or a live design challenge, I usually fail.
I know I have the skills. My work has always been well-received, and I've always received good marks on reviews and feedback, but I haven't been able to translate it to the interview process.
I've tried to assess where I go wrong, and I think I panic and put too much effort into trying to figure out what they want to see or come up with something innovative rather than just doing the work and following my normal approach.
The stress of the time crunch (and sometimes not knowing anything about the product or problem) only add to my inability to improve in this space.
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When I've sat on the other side of the table, I know that most interview processes aren't that well-structured or set up to actually evaluate the candidate. Even when there's a good process, it's often too easy for one person to influence the results.
So sometimes I tell myself that it was a crappy interview process and it just wasn't set up for someone like me to succeed. But I still end up stewing over it and feeling depressed for a few days.