"We officially recommend having an Exchange Server on-premises to handle those applications or devices if they cannot submit emails directly to Exchange Online. Read more about it here: https://docs.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365"How this should be performed? On the local server a receive connector is required that accepts the connection from printers and scanners then a send connector with TLS towards O365 that transfers them towards O365 like it's written in this article?
https://docs.microsoft.com/en-us/exchange/mail-flow-best-practices/use-connectors-to-configure-mail-flow/set-up-connectors-to-route-mail