I have just completed a run that I'm about to submit but I played on the Series S to achieve it. Am I the only one who thinks that the new next gen consoles should be added, or should I just pick the wrong console that I achieved the run on?

The leaderboard mods can add that as an option. Just ask one of them.

Also they're hidden under "Obscure" until they're used by something like 2% of the games on the site (or some threshold). And we might not be there just yet with the new consoles