I recently started building VR apps for VR headsets with Kotlin/Android after five years as a front-end/full-stack engineer. It has been humbling and scary, but I'm learning and loving it. The switch was motivated by several reasons typical to FAANG companies.
I see this a lot, but I will go out on a limb to tell you ADHD is not the reason for your failures. You probably already know this, but it feels better to blame it on something you think is beyond your control.
No, Leetcode interviews are very much alive. I have interviewed at all three companies you mentioned for frontend roles & they all ask Leetcode questions, but to varying degrees.
FB: I currently work here.
LC style questions but with a frontend twist. Best believe if you don’t have a strong handle on algorithms, data structures and Javascript, you won’t stand a chance.
Google:
Phone screen is leetcode, during onsite they ask two leetcode questions & 1 frontend focused one.
Apple:
Phone screen is Leetcode, onsite is a combination of leetcode & frontend.
I actually find frontend interviewers to be harder because you have to have a strong handle on frontend technology + data structures and algorithms, as opposed to non-frontend roles where just doing leetcode is all you need.
Also, there is the very wrong notion among people ignorant about the frontend engineering world like yourself that assume all it entails is simply knowing how to use React & CSS. It is more complex than that, you’d have to know about the DOM tree, know how to manipulate it, think about accessibility & performance. It can become complex very fast. Most of these interviews create Leetcode style questions from DOM tree manipulation & they are harder to reason about.