Safe, simple, low-investment build for normal [Ash]. Exilus can be anything, but you can probably just wait until you get [Ash Prime] to fully invest in him. This build will easily handle normal star chart, and can do Steel Path as well when supported by good weapons.
If you want, you can swap [Augur Message] for any of his augments (the armour strip from Seeking Shuriken is probably the best option), but I don't find that largely necessary.
Here is an endgame Ash Prime build https://overframe.gg/build/500478/