I think My Hero Academia has easily the most potential to reach the 400 chapters mark (unless sales start crashing lol). It has finally reached the peak of the Rise of the Villains Saga and that should be midway through, plus there's a lot more to be uncovered. Tabata wants to go on for a long time but with sales either hitting a plateau or decreasing (not to mention certain rumours about the anime), I don't see Black Clover going on for that long, maybe 350 chapters? It's the most uncertain one out of the entire veteran roster.
Chainsaw Man and Jujutsu Kaisen are both series that feel like they won't run for more than 250 chapters, I wouldn't even be surprised if Chainsaw Man ended around chapter 100. Dr. Stone should be around 250 chapters or maybe 300 at most. Undead and Unluck, albeit full of creativity, doesn't like it can last for an extended period, maybe 150-200 chapters. Same for Mashle. I can see Yozakura lasting until the 100th chapter. The rest are mostly gags/comedies and those are as unpredictable as they come and We Never Learn which we already know it's going to end soon.
I mean you can say the same about Harem or Ecchi and look where we are.