Until retired as a professor, I used Thunderbird and the GPG plug-in to sign emails. That makes them immutable no matter who hosts the email server you use. I encrypted the emails holding grades, if the recipient said they were able to decrypt. Setup was non-trivial but very doable. I also used (and still use) a plug-in that clearly shows if any email fails DKIM or SPF (I think DMarc too).
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Until retired as a professor, I used Thunderbird and the GPG plug-in to sign emails. That makes them immutable no matter who hosts the email server you use. I encrypted the emails holding grades, if the recipient said they were able to decrypt. Setup was non-trivial but very doable. I also used (and still use) a plug-in that clearly shows if any email fails DKIM or SPF (I think DMarc too).
Thank you! Will look into this setup!