Garen is both extremely tanky and can deal a lot of damage, that is his nature as a Juggernaut (and no a juggernaut is not the same as a tank). people are complaining about the natural characteristics of a juggernaut, which is literally “if he gets to you, HE WILL KILL YOU”.
Mean while Ashe is extremely squishy and is even more immobile than Garen. now don’t try to argue with me saying “BuT sHe hAs A gAiNt StUn On hEr uLt”. If you played Ashe for a while then you know that her ult is damn near impossible to land on champs that have lots of dashes, blinks, invisibility and more. Take a Zed for example, he has thousands of ways to dodge your ult, he has W, the first part of his R, and he can go back to the cast point of his R. He can flash behind/away from you before you cast R and he can use a stopwatch to deny the R stun.
Ashe is annoying for immobile champs, but she isn’t broken. Her utility and damage is gated by her utility and squishyness. When she gets behind (which is most of the time), she becomes an easy target for the enemy team and is basically free gold most of the time.