My problems with Spotlight started with Ventura and have persisted with Sonoma, but only on my M1 MacMini. Spotlight works with no problems on my MacBook Air (2020) running both Ventura and Spotlight. I don’t use Spotlight to search for anything - I use Find Any File and EasyFind. But I have Spotlight active on the MacBook Air so that I can use Alfred.
I had the same problem when I had Contact active in iCloud. Duplicates appeared on MacMini, MacBook Air, iPad, and Iphone. Now I keep Contacts synced on the 4 devices by downloading Contacts vCard from MaMini and transferring it to the other devices.
Sonoma also stopped syncing my calendars from MacMini to iPhone, as has happened to many as reported in Apple Discussions.
@MacWish6 I found a fix for the Spotlight problem. See the last entry here: easiest way to force spotlight reindex | MacRumors Forums
Unfortunately, none of the suggestions worked and spotlight remains disabled.