Dunno if it's just my bubble, but AO3 feels like the last real stronghold for this pairing lately. I've seen some solid stuff there—authors who really get their dynamic, the whole 'sunshine and storm cloud' tension. Wattpad still has archives, but you've gotta dig through mountains of 'reader insert' stories and it's kinda depressing how many of those have eclipsed the actual character-focused work. The dedicated communities I used to lurk on, like specific forums, have mostly dried up or moved to Discord servers you need invites for, which... fine, I get it, but makes discovery rough.
Honestly, the quality bar seems tied to who's still actively writing them. A few authors I followed moved on to other fandoms, and the newer stuff can be hit or miss. I found one author on AO3 writing a slow-burn that nails Andy's sarcasm, tags it really well, gets the voices. That's basically the gold standard now. Outside of that, it's mostly reposts or abandoned WIPs on older sites.