Devil Dinosaur isn't the problem, the problem is that DPS aren't adapting.
Ever since DD's release, I've noticed something quite interesting with the end game stats of every match I've been in : The losing team always has lacklusters DPS players while the winning team always has an extremely high blocked damage stat on their Dinosaur.
And I feel like that's the crux of why so many DPS mains are angry and whining all over the place since Devil Dino's release : They have to actually be strategic with their picks for once.
DD is such a gigantic pool of HP, both literally and figuratively, that most immediatly think they need to focus him. But if you're playing DPS, Devil Dino should NEVER be your primary target. By going for him, you're just feeding for his and both healers's ults.
With him around, you can't just shoot down the tank and everyone else afterwards, you need to focus his healers instead. Without them, he can't survive a single second.
DPS mains, this is why you're losing. It's not because DD is OP, he has very clear strengths and weakness, it's because you're still in the mindset that you can just run down the entire enemy team head first. But that's not your role. Your tanks are the ones that should focus on tanking against DD while you destroy the backline, not the other way around.