Is Apple silicon ready for Mail clients?

Yes

ApplicationM1 optimizedRosetta 2M1 Supported versionContribute
Mimestream - 0.9.2
Newton 🚫 ⚠️ Soon (Feb. 5th)
MailMate 🚫 ⚠️
Spark 🚫
Airmail 44.5.1

✅ Fully compatible with Apple silicon (M1)
🚫 Not working
⚠️ Initial support or Beta with issues/crashes reported