Is Apple silicon ready for Mail clients?

Yes

ApplicationM1 optimizedRosetta 2M1 Supported versionContribute
Spark ⚠️ 2.10.0.455 Beta
Spike3.2.2
Mailbutler14659
Newton
Mimestream - 0.9.2
MailMate 🚫 ⚠️
Airmail 44.5.1

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