I don’t think there is a right answer to this question, just opinions and preferences, so I’ll give mine.
I love when the priests mic gets left on or pics up some part of his prayers or singing we might not normally hear. Especially if they aren’t the best singer. It’s like a little humble earshot from their heart.
Alternatively, if they love to sing and it brings them such joy that they do it loud and boisterously, whether they are good at it or not, I find their joy for it is infectious.