I was a fifth, sixth, and (if necessary) seventh inning guy in HS, but a starter in American Legion. It’s a totally different regimen–starting vs relieving.
Remember that the warm up pitches should count toward your pitch totals as a reliever. Often I would throw at least 15-20 full intensity pitches in the pen before entering so that I knew I was locked on before hitting the mound in a dirty inning. There is no time to work things out unless you are starting an inning clean. I also would only throw 2-3 pitches between innings. Fastball, curveball, and / or change up (coming down).
Starting, I would only take 4-5 pitches from the mound entering the game then a change up for the throw down to second base.
Over the course of a game, you can save yourself an inning of work just in reduced warm up pitches you really don’t need but simply take because they are given to you.