I'm writing because the solution I found doesn't show up in search.
When opening the print dialog in any application, Microsoft Print to PDF no longer shows as an option. When navigating to Bluetooth and Devices > Printers and Scanners, Microsoft Print to PDF shows as disconnected.
MY SOLUTION: In the Start menu, run Services. Scroll to the Print Spooler service. If the service is running, restart it. If not, start it. This immediately fixed the issue for me.
If this doesn't solve your issue, refer to these past articles for more in-depth troubleshooting:
microsoft print to pdf not working - Microsoft Community
Microsoft Print to PDF. Shows status "unable to connect". - Microsoft Community
Troubleshoot PDF printing in Acrobat and Acrobat Reader
\[Solved\] Microsoft Print to PDF Not Working in Windows 10/11 - Driver Easy
These didn't solve the issue for me but seemed helpful to others.