Is an S impossible in aram?

For a while I got all my boxes through ARAM; sometimes the bar is just really high because how uneven matchups in ARAM can be.

You really have to get lucky to get those S ranks in ARAM. Not only do you have to roll up a champ you need a chest for and have a great game, you also have to hope the enemy team didn't roll up any champs that absolutely shut you down. For instance, it's hard to have a good game as Xin when the enemy has Rammus, Taric, and Malphite.

I've seen / had a few. It's just really rare, you need some insane scores for it.

I just got an S in aram with aurelion sol

21/9/33 98 cs 28 minute long game

No, but it might be harder because roles don't exist there.

But you know how random ARAM can be, this difference could be a huge factor in grades due to weird team compositions and poor/strong match-ups.