As for the evil schemes, it was clear that Venomous himself (before he met and started cooperating with Shadowy Figure) had some plans for (T)KO, but it was never explained what those plans were. He obviously experimented with turbonic energy before, seeing that he invented turbo collar and backpack for Fink, and he literally spent entire season dropping hints about TKO to KO, and then nothing, zero payoff. The entire "evil villain but with an eviler split personality!" thing was dumb IMO. That "who would've thunk that my son would be able to harvest the power of glorb tree" bullshit from the finale was dumb too. Or the way he found out about having a son.
Overall, PV just didn't make sense as a character. The twist with Laserblast being Venomous was super obvious, but still, I had a hard time accepting that they're the same person, not only their appearance and personality were completely different, but also their quirks, things like LB's lollipop addiction disappearing, or PV's snake motif that came out of the blue.
His backstory was messy too, every time we got new bits of information they didn't exactly add up with what was stated before. For example, when Venomous proposed the merger with Boxmore, he made it sound like his beginnings as a villain were the same as Boxman's, and that's why he sympathizes with Boxman, respects his resolve, and wants to be with him to return to his own roots. Except that was bullshit, because his beginnings were the exact opposite of what he implied. So why did he even like Boxman and married him in the end? He went from dating 10/10 Stacy, to settling for a fat autistic fuck, pretty sad end IMO. I actually liked this ship at the beginning, but by the end of the show I wanted them to split up.