Sorry, unfortunately I didn't find any Sermons

No, I followed those instructions as well.

Hmm, looks like it didn't apply the migration SQL file then. I don't know why, it should work

You can do that manually using phpMyAdmin or a similar database management tool. If you look at the zipfile for SermonSpeaker 4.5.4, you see a migrate.sql file in the root of the zip. This contains all the needed database changes to get your database ready for 4.5.4.
You can adjust the prefix from `#__` to you Joomla prefix (eg `jos_`) and then run it in phpMyAdmin.

Or you can just try again the whole migration using the steps in the FAQ. You should get a message that the database migration worked after the second installation of SermonSpeaker 4.5.4 (after the copy of the old database tables).

I kind of know my way around databases, but I just want to confirm that by run that migrate file you mean import? If that is what you meant, it didn't work. I got an error.

As for starting over, I've done that twice. This church would really like to get the new website going. Any chance I could get you to take a look? I'm about at my wits end.

Importing should work (after you adjusted the prefixes). However there may be errors because you already updated SermonSpeaker to a higher version. Maybe then some commands fail because a field no longer exists or something.

I could do it if you send me logins for the Joomla backend (new one) and for phpMyAdmin (old and new database). You can either use the form or email at bakual@bakual.ch.
I may have time tomorrow evening.