The first thing to mention is that you do not really increase your privacy with individual addresses. In my opinion, you can ingore this requirement right away.
If you collect donations on 200 addresses and want to cash them out, you eventually will send out a transaction clustering them. if you use coinjoin or other mixing services, you risk your coins being frozen by exchanges.
If OP customer really have serious privacy concern, they would use method to reduce the link/connection. For example, they could use P2P or multiple exchange for each/few addresses.
So lets ignore this right away and you can easily use 1 address only for all donations.
This is horrible for donator privacy. The moment they send Bitcoin to that address, blockchain analysis
immediately know the group receive donation.