I also rely on IEM only, but am thinking of bringing an extra monitor for some speaker-strings interaction. Can be very helpful, if you‘re as mediocre as I am 😂.
I've been on rotation at my church for ten years with an acoustic drum set, no plexiglass cage, just cymbal shields.
If you're playing worship music....a monitor won't matter. Not even a little....and as DonPetersen said, it will screw with the FOH mix.
You might like it, but it won't be because of string interaction.