Alternative to Apple's buggy Preview

I have not experienced the problem you mentioned, but as a heavy user of annotations in Preview I would be terribly frustrated by this.

Did you try Skim? It is free and a long time mac application that is still getting frequent updates. It works fine in Ventura.

When I use Preview on the local filesystem, or a document on iCloud Drive, it autosaves my annotations 100% of the time — unless the PDF has permission limitations, or I have chosen System settings to prevent autosave. Pick any macOS including Ventura 13.1. I can't speak for the Preview product team, but I suspect they do not guarantee or test its behavior on brand x network servers, or non-Apple cloud services.

It would be a stretch to assume that the Apple product teams have spare time to expend scanning online forums for issues. There are proper feedback methods for that. Being on a development team is all consuming of one's time and more often than not eats into late nights. I can speak to my own experience of 90 hour work weeks as a non-Apple developer.

The free Skim application, as suggested by Luis, is purpose built for annotations. Adobe Acrobat Reader DC can do that too. Skim, like Apple's Preview, is based on Apple's PDF Framework PDFKit. It also has a command line component useful for manipulating PDFs and is AppleScript aware. Once you select a PDF annotation tool, it is wise to stick with it as some of Skim's annotations may not appear in Preview or Acrobat Reader DC.