Tanks are like supports in that they don't have as much agency as other carry-oriented classes. They can initiate or peel like a god, but at the end of the day if their team just isn't on the same page it's hard for them to carry themselves.
Also, don't believe all this hype about "tank meta" or "tanks are strong". Outside of Poppy (who got nerfed last patch, and is about to receive another nerf with all the other tanks when the CoC nerf patch goes through) tanks really aren't very strong. People tend to confuse juggernauts, divers, bruisers, and assassins built like bruisers with tanks and then claim they're overwhelming. "Tank Ekko" isn't a tank, he's a bruiser.
Bottom line: If tanks were indeed so strong right now, more people would be playing them. No one is, outside of Poppy. Back in season 5 when Cinderhulk made tanks strong, you rarely saw a team comp that didn't have 1 or 2 tanks in it. That is what a tank meta looks like.