>>40877733Average defensive typing, outclassed by pure water in terms of raw lack of weaknesses. Decent defense and special defense, but garbage hp means that Toxapex doesn't take hits very well. The only promising set is probably toxic spikes + merciless venoshock, but that would probably be a joke set at best.
As fun a pokemon as Toxapex is, there really isn't any way it will be viable competitively in Gen 8.