To check if you’re walking on a surface, you’d need to perform a trace from the character to straight down to the ground. There’s already an automatic trace going on even though you don’t do it yourself. The way I explained, you’re essentially recreating that trace required for movement, just a little further away. So that’s what you’d need to do in order to achieve your objective, one way or another. There isn’t a setting to adjust for this other than the capsule radius.