You can use BTCPay integrated with Payjoin [1] to make your transaction will not linked with each other, but you need to host yourself to run BTCPay with some requirement 4GB RAM and 500GB hard drive [2]
But the problem of BTCPay with Payjoin transaction is most of wallet still doesn't support Payjoin, because your customer should use a wallet that support Payjoin or the transaction will be linked.
[1]
https://docs.btcpayserver.org/Payjoin/[2]
https://bitcointalk.org/index.php?topic=5259548.0Hello,
From their website it seems they help you provide a unique btc address to a paying customer but not vice versa, i.e. provide a unique sending btc address for each transfer sent to a customer.
What kind of wallet would not support a payjoin transaction? We certainly can't ask customers to sign up at something like that, nobody would want to do the work!