Arduino equivalent for Dronekit

I’d like to replace my Raspberry Pi which flies autonomous missions with an arduino because they’re much smaller, what options to I have for programming, is native MAVLink the only choice and if so how hard is it to learn in comparison to dronekit or is there an equivalent for dronekit for arduino’s?

There is a thread in this forum about using arduino as a companion computer, talking mavlink to the autopilot. Read that.