Have you studied extensively for the technical exams? I've tried, and I've gotten interviews at several of the FAANGs as well as some desirable mature startups, but I fail at the technical screeinging stage. Not sure if I've tanked it or was close, but I get the "no hire" call or email after take-home projects or whiteboard exams.
Btw, to give you sense of it, I'd have no trouble finding a loop in a linked list, printing all permutations of a set, or searching a tree recursively. I'd have to puzzle a bit to figure out how to do DFS vs BFS, but I'd get there, I don't have it loaded into memory. I wouldn't be able to implement merge sort on the spot, I'd need to look it up, though I could probably get it frontloaded. All I can say is dayum those interview exams are hard, what I described is a pre-req, nobody will just ask you to permute a set, but if you can't, you'll never solve whiteboard the problem they ask you in 45 minutes.
For take-home projects, one (a rails app) was rejected because I used named routes rather than using the more conventional methods (I know this wouldn't be good to do in a production app... guess I just wasn't thinking about routes, it was a demo app, so I just threw some names routes in there for demo purposes, it was a take-home), along with some "duplicated" code that I thought was justified but never got to explain (I personally think extracting this into another method would be a pre-optimization that would need to be undone when the methods diverged, something I thought would be likely under the admittedly fabricated business requirements). I did have what I though was good testing, the reviewers did complement that along with some aspects of the app in their review.
Sorry, don't mean to give you my sob story, I just... I'm at the point where I wouldn't mind a crack at these jobs but just feel like maybe it's not an effort that's going to pay off (I mean, how much more time do I really want to spend on the kind of problems in cracking the coding interview? I actually feel like I got something out of studying it and preparing, but going back over and over, nah... maybe other people retain this stuff better than I do, and you know, maybe that does actually say something about suitability for these jobs).