Unless they've changed it since a couple weeks after Shadowbringers dropped, yes, they all play pretty much similar within the same role. Since they fucked Astrologian, all healers play pretty much completely identical to one another and all tanks feel virtually interchangeable with one another (a real shame since Paladin used to have some really interesting meta vis a vis a shield ability that actually shields everyone behind the Paladin in a line, an ability that was almost immediately nerfed except in one or two particular boss fights). All DPS roles play almost completely the same and the only real factors are some classes depend more on positioning to maximize damage. The only really unique ones are Blue Mage - a class that only learns spells by being the victim of said spells, which would be a super cool class if it wasn't limited to level I think 40 or 50 and as a result is not viable in any way as a main class - and Red Mage, which needs to balance White and Black mana usage in order to maximize effectiveness. Everything else is essentially the same shade of "use this cooldown then use this ability".