When is the best time to apply sunscreen before going out?

As the weather gets warmer these days, the UV index seems to be rising, so I'm trying to apply sunscreen more diligently. However, a question suddenly occurred to me, so I'm asking the community members. Is it best to apply it right before going outside for the best protection? Or should I apply it 30 minutes before, allowing time for the sunscreen to be absorbed into my skin? Everyone's advice varies, so I'm curious about the exact information.

Some people say that you have to reapply it frequently to maintain the effect, but it's actually not easy to reapply it over makeup. I'm curious to hear reviews from people who have used products like sunscreen to see if it's okay for makeup to not smudge. I'm writing this because I want to completely block UV rays, which are said to be the main culprit of skin aging. If you have any professional know-how, please share even a small tip. I'll be waiting for your comments.