Hello, first time poster here. Last night looked up and tried to find an answer to why my back was so slow I’m running Sonoma, 14.1.2 OSX. And the latest SpamSieve along with Apple Mail. And mine was seriously slow as well. I looked at the amount of rules that were allowing email in and it had reached 69,000+. I went through and deleted probably 45,000 of those rules, they were all allowing the list-unsubscribe (sp?) in the Location field.
My symptoms were that Apple Mail would hang for 20 to 30 seconds at a time and it was very frustrating. At the moment, at least for now, I am not receiving any of those hangs. Hope this helps.
[Edit: please let me know if you want any other details about my set up]