For pretty much all intents and purposes, Walrein is a worse Lapras in PvP, which is probably why it doesn’t have a PvP analysis. Its quick moves both generate energy slowly, which doesn’t mesh well with its high energy charge move options. For Water-type coverage, it’s limited to Water Pulse which is strictly worse than Lapras’s Surf (and is a pretty bad move in general). It also has less bulk than Lapras, so it can’t soak hits quite as well.
I think even Cloyster fares better in PvP compared to Walrein by virtue of having access to Avalanche (crazy good move) and Icy Wind (debuff shenanigans).
Edit: Walrein does look creepy though. It’s a damn clown walrus! If your opponent has a fear of clowns, they may just concede? So it has that going for it.