It became even harder once Ethereum became non-fungible thanks to Tornado Cash and OFAC.
What do you mean by this? I haven't been following this space for a long time and searching only brings up NFT stuff.
fwiw, the person you're responding to doesn't seem to be using the word in this manner.
There are no shades of fungibility, it's a binary state.
Btw, calling Tornado Cash a "DPRK tool" is disingenuous. It's a privacy tool.