Could you explain the method you’re using in more detail, please?
I only know three ways of memorizing texts verbatim:
The John Place Method
You can read about this method here. It’s basically about applying active recall to the text. It’d be beneficial to use some spaced repetition software, like Anki, to schedule reviews as well.
Initials Link Method
I invented this name, but it seems that nobody knows who came up with the method itself. The earliest source, and the best explanation, I’ve found is on this website. You can also practice this technique using your own texts on the software available here. If you wish to watch an explanation, instead of reading one, Nelson Dellis has a video on this method.
Memory Palace
This isn’t practical, but some people have managed to use it. Basically, since memory palaces can store lists, you could see a text as a list of words. Needless to say, that is simple in theory, but horrendously difficult in practice. If you want to understand more about it from an actual user, I recommend the book Solomon’s Memory Palace by Bob Lingerfelt. Despite its focus on freemasonry, you don’t need to know anything about it to learn from the book. Although I’ve never applied his technique, I find it super cool, and this is certainly one of the most interesting books I’ve read on memory methods.