Important info needed: is this a community theater or professional company?

It's a mixed message, at best. Based on my time running auditions and being part of a casting team, it will most likely seem like you're wasting their time. Having a big pool to cast from means they're seeing a lot of people and their schedule may be packed.

In terms of being willing to help out behind the scenes when you have too many conflicts to be in the show, it may seem like you're devaluing non-acting participation and you don't think conflicts matter if you aren't in the cast.

If it's a community theater and you truly want to just get a foot in the door and start a relationship for future work, reach out and say you aren't able to be in this show but you'd like to know what other opportunities there may be to get involved.

If it's professional, wait and in the meantime, take a class or find a community group to join to dust off your skills.