I didn't like the pick to begin with (because of positional value) but no way we should be worried about any player one week into their first ever training camp. At the very least he apparently isn't standing out in a bad way. A 2nd round player getting rotated between the 1s and 2s is exactly where he should be at IMO.
Honestly my biggest concern at safety is that Rapp is apparently locked in as one of the starters, getting all 1st team reps so far, and I wish he had some legit competition.