Ah I think I sort of misphrased my original question; I meant that for add/unlock achievement progress in BP, is there a node that would allow me to do this for Epic Games Store achievements? In Steam, I would simply define the achievements in the Subsystem backend and change the INI file like you said, then I would add a node “Write Achievement Progress” after a certain action to actually unlock the achievement.
However, I saw a few answers saying that this node won’t work for writing Epic Games Store achievement progress, since EOS achievements are not exposed in Blueprint nodes. So I was wondering if this was true, and if so, how I would actually write the achievement progress using nodes? Could I just use the same node as adding Steam achievements?