First off, SpamSieve is an invaluable part of my life - thank you for all the work you put into it.
Today updated to the new 2.9.52 release. Immediately after trying to launch AppleMail causes it to hang indefinitely. Tried safe mode, tried rebooting computer in safe mode, eventually deleted the SpamSieve bundles in ~/Library/Mail. Mail now opens.
Tried reinstalling SpamSieve, same result - Apple Mail will not open and hangs on launch.
macOS Ventura 13.2.1 (22D68)
Apple M1 Max - MacBook Pro
It did eventually unfreeze when left unattended for some period of time. Not sure if that was a combination of rebooting in safe mode, deleting and re-adding, etc. Attaching the report just in case it gives insights.