I believe that “Grain Theft” technique is similar. Not using an obscure Photoshop filter thankfully.
There are a few ways to skin this cat.
Subtract the original from the denoise and then add the result back further up the chain to restore the grain.
Recently there was a post about how that gave less than desirable results in ACEScg.
Someone much smarter than me suggested doing a multiply and then divide further up the chain to fix this problem.
Sounds good but I havent tested this yet.