I suspect it's going to take a lot more egg shells than that to have too many, but maybe someone else knows for a fact. Just make sure you throw them in a hot oven before you compost them. You want to hold them to at least 160F to kill salmonella. Some places recommend 250F for an hour. I generally have them around 350F for 30-40 minutes.

This accomplishes a few things:

1. It kills the salmonella
2. It makes them easier to break into small pieces
3. It allows them to break down and extract the minerals far more easily in the compost

With how many you're going to be composting, you may want to find a method to really grind them finely, towards a powder. I'd imagine that will allow you to compost more, without reaching some possible negative points like too much aeration to the soil. Though you might lose some benefits, like the pest deterrence, or maybe not since some people just sprinkle egg shell powder on top of the soil and leaves. If you're going to limit how many you compost, you might reserve some powdered egg shells for this purpose.

If you're worried about attracting animals to your compost, rinse the shells before baking.

Just a thought, but for your volunteer baking, could you reduce the number of eggshells overall by partially or fully substituting the eggs with flax eggs, egg replacer, or fruit mash such as applesauce or banana? That way, you only have your home eggshells to worry about. I do a lot of vegan baking, so if this is a path you’re curious about I’m more than happy to help if you give me an idea of what you’re making :D

One of the best ways we're aware of to make the calcium plant available is to treat them with vinegar. We'll dry ours on a sheet pan in the oven on a low temp, crush them, and then steep them in apple cider vinegar for up to a few days. The remaining bits of shell can be strained out and added to your bin, and will break down much more quickly than they would otherwise. The acv solution can be diluted 10-20x with water and applied at the base of your plants or as a foliar spray.

Some of these solutions sound more energy intensive than just throwing the eggshells in the garbage. Can salmonella really survive the composting process enough to contaminate food that would be grown in the compost?

Some cities have composting options. You might check what your community has. We compost our own stuff but I think I remember my wife saying there was a community option too.