I haven't asked a whiteboarding question to candidates in years. In fact, the only questions I ask are based on real-world problems I ran into that can be solve

I haven't asked a whiteboarding question to candidates in years. In fact, the only questions I ask are based on real-world problems I ran into that can be solved (or at least started) in an hour and can evolve over time. One way to source these questions is to observe whenever you have a small product ticket that requires some algorithmic or systems design complexity. Strip away all of the proprietary data and IP and see if you can create a problem around the real-world thing you experienced. If you can constrain it to a solution in 10-25 lines that takes less than an hour to create, you can feel good knowing you've got a real problem with a real solution to give to your candidates. Also: let them use Stack Overflow/MDN/Google. We use it everyday at work, why should you hold that back from your candidates?