Actions disappeared

More here, including the paths to the .psp file:

https://prepression.blogspot.com/2017/01/photoshop-custom-action-file-backup.html

Actions are stored in your preferences file, in your user account. Every version has its own unique preferences.

You should always save out your actions, brushes etc. They will not be migrated to a new version, and they will be wiped if for instance you need to reset preferences for troubleshooting purposes. You save them out from the fly-out menu in the panel. Keep them in a safe place so that you can reload them as needed.

The preferences contain the entire app configuration, and your settings in one version may not be directly applicable in another version with new base code. That's why they don't automatically migrate.

If you still have the previous version installed, save the actions out now. If not, look for that version's settings folder in your user account. Maybe they can be retrieved if you kept preferences when you uninstalled it.