can't sign in to my Microsoft Edge account

When you sign in to Microsoft Edge with your Microsoft account username and password, you can choose to sync your bookmarks, passwords, open tabs, settings and much more to your Microsoft account. Syncing means that you're storing these things in your Microsoft account, so they are always available to you each time you sign in to Microsoft Edge with the same Microsoft account username and password. On the other hand, if don't sync to your Microsoft account, these things won't be stored in your Microsoft account and can get deleted when you close Microsoft Edge.

If you weren't previously signing in to Microsoft Edge with your Microsoft account username and password, and then you decide to do that, what you had previously in Microsoft Edge can get deleted when you close Microsoft Edge, so it won't be available to be stored in your Microsoft account.

If you were previously signing in to Microsoft Edge, but you weren't syncing to your Microsoft account, and then you decide to do that, what you had previously in Microsoft Edge can get deleted when you close Microsoft Edge, so it won't be available to be stored in your Microsoft account.

If you were previously signing in to Microsoft Edge, and you were syncing to your Microsoft account, and then you decide to sign in to Microsoft Edge with a different Microsoft account username and password, what was synced to the first Microsoft account won't be available in the second Microsoft account.

These are the scenarios that apply to you. If your bookmarks, passwords, etc. weren't stored in your Microsoft account, they are likely gone.