Part of macOS
oahdRosetta
○ Leave it
Translates apps made for Intel Macs so they run on Apple silicon.
What it is
Rosetta 2. It translates an Intel app once, then keeps the result.
Why it might be busy
The first time an Intel app opens, or after it updates. Usually a minute or two.
If you stop it
macOS starts it again straight away. Leave it.
The verdict
○ Leave it. Part of macOS, or something that starts again by itself. You never need to close these.
In Activity Monitor
oahdoahd-helper
From Procession’s guide, in the words the app shows.