And you found it yourself!
(But I am thinking you didn't take the earlier advice someone gave you of spraying either water or carb cleaner on your engine to see if it either sped up your idle or slowed it down.)
But congratulations anyway!
That 360 will be a runner for you, but yes, sadly, it is a bit of a pig.
Your idle has normalized. That is the idle speed locked into the pcm.
Thanks for the follow up.
Now get yourself a spray bottle and fill it with water just in case
You don't need the extra headaches of an engine journey like this again.
At least you learned a lot of stuff and taught us some as well.