Can't open PDFs in browser

Safari 15.2 on Monterey 12.1 - PDF links in web pages. Safari will not open a PDF without downloading it, no matter what I set in the various recommended places,. I have unchecked "Open safe files after download" and tried a dozen other solutions. Right-clicked, control-clicked. Tried six different sites as source of PDF. Restarted. Apple docs say the normal behavior is to open PDFs in the browser. What's up?