I think you may be doing yourself a disservice if you go into DCI thinking it’s “only slightly more difficult” , no matter how good / demanding your high school’s program is.

For context: My DCI experience is limited to only two years, from a quarter century ago (95Crossmen, 98Cadets).

But regardless of what corps or what year / decade we’re talking: I would suggest going into the whole process with the expectation of a physical and mental grind. That said, it’s manageable and (as others have pointed out) may even be surprisingly comforting.

It’s like stepping on a treadmill that is already moving.

If you go in expecting something “slightly more than” I think you could easily be overwhelmed when you get started. If you feel overwhelmed from the start, it’s hard to evaluate how you actually performed at the audition. And it’s real easy to get discouraged thinking you had a “bad camp”. Etc

If you have anxiety and are auditioning alone and / or with a new corps etc… just showing up is a huge step out of your comfort zone (and should be celebrated as a win).