Obvious thing any merchant could to is to enable / integrate Payjoin (supported by BTCPay Server). Not only it increases privacy, also reduces receiver's UTXO set, so you can always argue you are doing that to save on future transaction fees, not that you want to hide something.

Similarly you could receive into JoinMarket yield generator wallet, which would run in background and also not only increase privacy, but earn you some coinjoin fees and other parties will again pay for UTXO consolidation.