A nice way of accompaniment for A Dorian tunes (Am) is to put the capo in 2nd position and play in Gm. This way you can use the G-string and or the D-string as drone (with capo then A and E).
I made a chord chart with lots of chords for this occasion:
As an example here are some possible chords for the tune Castle Jig. Your ears have to decide what sounds good for you:
I found this nice version of the Castle Jig, so this one might be used to try to accompany.
This is Kevin Burke teaching the Castle Jig. I cut out his performance and looped it, so I could play along with him. I used some of the chords shown above in the chord sheet. I had lots of inspiration from the Guitar Course at OAIM which is well worth a look at, even for players of the bouzouki. https://www.oaim.ie
Here's a second video with some slightly different chords:
Here's a little chord chart I made some time ago. Chords in higher positions for G-Minor. With capo on the 2nd fret this is useful for tunes in the key of A-Minor. Just play along and have fun.