About 2015 we switched our web and email hosting to Rackspace. Then "Cloud Computing" decimated Rackspace. We switched web hosting to Digital Ocean in 2018.
Email is currently still with Rackspace (not MS Exchange). They asked us a couple times a few years back to find another email provider, which I'm ready to do.
I know Google can get the job done (or so I think), but that's about all I know. I learned of DMARC at the 2020 PyTN conference.
If anyone has experience in this area, I'll take all the advice I can get (needless to say I'm not interested in MS Exchange).
Thank God for NLUG