Is there a way to replace missing title effects?

I have a couple of projects I worked on 3 years ago and now I have to work on them again.
At that time I made a custom title effect in motion for adding subtitles, which I don't have anymore

Now when I open a project naturally I get the 'missing title' sign and for some of the titles I can see the actual subtitle text in the 'Name' field in the Info tab or in the Timeline Index.

So, I am desperate to find a workaround for replacing the missing title effect with any other available, so I can retain the subtitles - unfortunately hundreds of them.

Is there a workaround? Any way to edit an xml and reimport?

Thanks in advance!!