The problems at work are also real, actual problems.
I have trouble with the coding section of the interviews but I do know how to write code. If the coding section of the interview was like "build me a ci pipeline for this app" or "find all the workloads in this cluster which need X attribute" or "design a terraform module to do Y" then I would pass with flying colors.
In the average SRE role, it has been my experience that there are very few situations where I would need to build out a perfect O(1) algorithm. Nothing I write is going to be so heavily used that this level of performance is something to be concerned with. These are the only code problems I really see when interviewing though.