If you're buying a console for one game, and that one game is Gotham Knights, you may want to reconsider your approach. I'd honestly hold out for the thing you want (in this case, a ps5) as opposed to settling for less. Buyer's remorse is a pretty bad feeling.

You did well by identifying that Xbox has no next gen (current gen, really) games yet. I usually recommend Series X over Series S because the $200 difference can be made up if you buy memory or if you find good deals on physical discs. I mean, just borrowing a couple of games that are $60 each can make up that difference pretty quickly. However, if you are really certain that you won't be playing it much and are ok with the lacking performance and disc drive, then pick up the Series S.

Overall, I still say hold out for the PS5 only because that's what you really want and it actually has next gen exclusives that won multiple awards last year. But, if you can afford the Series S and still buy the PS5 if one becomes available, then go for it.

If you buy a Series S and a PS5 becomes available a week later and you can't afford it, how would that feel?