Great project.
May I ask whom is doing the reading for the gospel of St Matthew?
Forgive me also for asking but are these books AI created/enhanced?
It is dulce et decorum to have Scripture read in an English accent voice. 
So, yes, AI was used, where various individuals read and then AI uses them. I actually had been thinking of using a clone of Bishop Williamson's voice, but they actually force you to say random things into a microphone to prove that it's your voice that you're trying to mimic.
Now ... there are no voices trained in Latin pronunciation or diction. For that I would have to read the passage in my own voice, but then AI can reproduce the cadence, pronunciation, etc. ... except in the other voice. I had tried seeing whether Italian or Spanish speaking voices could be trained to render passable Latin, but the pronunciation just wasn't close enough.
But, really, the primary reason I did this is that I'm so darn busy that I just don't have time for spiritual reading, but I drive often enough or do chores like mowing the lawn, other yardwork, and ... I also need to try getting back into shape (with about 6 years of working two jobs taking a toll), so I realized that if I could use time like that, I could actually do the necessary spiritual hearing / reading.
I didn't do this with the hopes of making money, but just for myself and my family, but it's just extremely slow going trying to get it done during my spare time. But if enough other people are interested enough and find value in them, if they contribute, then I could replace the 40 hours a week I spend on my second job with doing this and accelerating the production of these books.
Even with the AI, it can be very time consuming to produce these, because you often have to train the pronunciation, the tone of voice, etc. ... almost like the diretor of a movie, and often make corrections or fixes. It was especially time-consuming to produce the multi-voice Gospel of St. Matthew.
At first I thought I'd just do that in one voice, but I found the multi-voice to be extremely beneficial, not only because it could make the Scriptures a bit more engaging, say, for children, but also because if you're momentarily distracted by whatever you're doing, you won't end up lost as soon as your attention returns, wondering who's speaking or who's saying what.
In any case, even if I don't get a lot of donations, I'll just slowly drudge along, making them when I can.
I'm working on St. Paul's Epistles, as well as St. Alphonsus' "The Glories of Mary", and Mary of Agreda's "The Mystical City of God".
I was able to listen through the entire Gospel of St. Matthew in about half a week, simply by leveraging the time I spent doing things that were amenable to listening.
When I was at seminary, you had to put aside about 30 minutes of spiritual reading (partially Sacred Scripture, partially other works), but then you also had manual labor to do, typically between 30-60 minutes per day, such as, say, one week you might be assigned cleaning the classrooms, another week cleaning bathrooms, each day ... and most of that work did NOT require a lot of mental attention, and then you also had a couple recreation periods where you might often go for walks, and so you could also double up tha time with some additional spiritual listening.