I’d recommend building a reamp box so that you can experiment with any pedals and/or amps that you’ve got
A reamp box takes a line out from your interface and changes output impedance so that it works with guitar gear.
Jensen has published a schematic for this using their JT11P1 transformer
A reamp box can be really handy in the studio, there are tons of videos on YouTube showing different tricks you can do with them
There are some harmonica mics that are meant to connect to a high impedance amp like a guitar amp. I have one called the Electro Voice M43 and it can be connected straight into a tube amp for a lofi distorted sound, but you will usually get too much feedback if you try to use the amp and mic in the same room. It would be easier to record vocals and experiment with various dirt by way of a reamp box