If next was the next occurrence of the day you’d be saying “next Wednesday on a Tuesday” and be talking about tomorrow, which is frankly ludicrous. I’ve also never heard anyone use a rolling week for “this” and this is such a funny conversation to come up because I literally had this confusion last Sunday (not this previous Sunday, as in yesterday, also note that this lines up well with using “last week”), because I was talking with several Venezuelans, a Chilean, a Mexican, and a Salvadoran, along with some Americans and this exact confusion came up but not because it was a rolling week, or because next means the next occurrence, but because they considered the week to start on Monday, not Sunday. So “this Thursday” meant the previous Thursday, since it was part of that week. Next Thursday meant the coming Thursday (the part of the next week).

I mention the nationalities because it’s pretty uncommon to start a week on a Sunday like Americans do.

Weirdly I looked it up and the internet says those countries start their weeks on Monday but that sure wasn’t what the people I talked to thought. 🤷