Mail Indexing not working with Sonoma 14.1

Upgraded to Sonoma 14.1 and now Mail doesn't index properly. I have a huge mail database, over 4 million messages. Tried to perform a manual rebuild by deleteing the Envelope index files as suggested at https://nektony.com/how-to/rebuild-apple-mail. The import did not complete. Index didn't work. Tried again and it only imported a smaller portion of the mailbox. Same issue.

I've had these issues with my mail programs for decades. For some reason the developers never test on large databases. I hope this one will be fixed soon.