Do you use the SMTP Proxy?
I'm not confident with mail delivery between my M370 and exchange server 2019 (self hosted). Not getting some emails and I'm using the SMTP Proxy and spamBlocker. spamBlocker has Allow set to all so it's not blocking, I'm evaluating headers and letting Exchange mail flow rules handle the scores. I've tried just using the SMTP packet and of course the emails flood in, lot of spam. SMTP Proxy is only for inbound. I'm not sure I trust it. I'm using the SMTP Incoming Standard and then turned on spamBlocker and Gateway AV.
Are you using SMTP Proxy and if so is it reliable and trustworthy or should I just look for an alternative anti-spam system for Exchange server and use the SMTP Packet instead?