https://www.windowscentral.com/xbox-series-x-series-s-hard-drives

That’s a link of a quick search I just did to help give you an idea. You should do a little looking around online.

Here’s another link from Amazon

https://www.amazon.com/gp/aw/d/B08Y1Q2KSZ/ref=sspa_mw_detail_0?ie=UTF8&psc=1&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWwp13NParams

That second link is for an actual Xbox XS external.

But I am certain you can find a much cheaper external, just make sure it’s fast enough to be compatible with XS