Warning: unsolicited advice incoming. DFS, at least in the context of big-tech interviews, basically just means searching a 2D matrix, or a graph. It's not some esoteric 160 IQ PhD CS concept. You probably've implemented DFS in your day job without even realizing. I used to think algorithmic interviews were beneath me, too, but then I realized that attitude and insecurity was just getting in my own way.

I begrudgingly started treating LeetCode and CodeForces like a game, and it turned out to be more engaging than I expected. I'm also 30 with a family, so I get the time constraints, but just 30 minutes a day for a few months made a huge difference.

Put it this way: If someone told you, 'I'll give you $500k, top-tier career opportunities, and a resume that opens doors, but you have to spend 30 minutes a day for six months solving toy programming problems,' would your sincere reply be "no thanks"?