I see others have had this problem but I haven't found a clear explanation of a fix.
I developed many apps using my personal email as my login. At some point I was forced to shift to a Google account login. When I use that, my Projects list is empty. I can log in to App Inventor with my personal email but App Inventor switches me to my Google account login address.
How do I access all the apps I developed using my personal email login, please?
I answer dozens of these requests, so I don't know why you didn't find my response when searching.
The transfer process is manual. I do it approximatelly once a month. I can transfer your projects if you send me a private message with the following information:
The old address with the projects you want
The new address where you want the projects transferred
A description of the projects in the account
You send a private message by clicking my avatar image and then the Message button from the pop-up menu.