Hi friends! Nice to virtually meet you :)

Gonna have a lot of newbie questions in the next little bit, since I'm considering working towards being a professional Catholic church musician/music director at a smaller parish. I hope that's okay.

My past work has been as a music director at a smaller Presbyterian church and my current work is as a music director at a smaller Anglican church. Both have played a combination of traditional hymns and CCM. I've also worked in theatre. I both sing and accompany myself, as well as playing other instruments. At the church jobs, I've been allowed to make my own arrangements most of the time, playing by chords, by ear, or even reharmonizing things after reading the hymnbook arrangement. I've been told that my musical strengths are harmony, singing, songwriting, and playing by ear. I've also been told that I'm pretty decent at sight reading and transposing. However, my ability to become confident and consistent in playing music I've learned from sheet music is far, far below the average professional who plays traditional hymns, especially since I am self-taught on the piano. (BMus but not piano. Just started organ lessons though.) It takes me a ridiculous amount of practice to get to the point of performing any particular piece of sheet music well (unless of course, it's uber rudimentary). I know that I can learn the Catholic music exactly as is arranged in hymnbooks, but I don't think I could learn the arrangements for the eight-ish (?) songs a week that it takes to stay above water as a professional, starting out at a new parish with all new repertoire.

In the Catholic church, is making your own arrangements allowed? I know there are probably certain rules, like not making things too distracting. But are you required to play the exact arrangements in the hymnbook, even if you keep the melody the same? Also, are allowed to change the key?

Thank you so much!