Bethesda Game Studios historically releases a new game every 3-4 years. The most recent gap between major releases (Fallout 76 and Starfield) was nearly 5 years, I assume due to some combination of COVID and generally getting worse at everything. Starfield was released September of last year, so if everything goes well, could be late 2027, but more realistically 2028. If they can't get it out by sometime in 2029, Todd Howard is probably fired.

I'm skeptical that it would be a next-gen Xbox launch title/exclusive. No doubt they'll do a next-gen version, but given the development time for both, and the fact that neither has even a hint of a release date, it seems like it would take a lot of coordination to get that to happen. Plus, I doubt that Bethesda would want to release exclusively on a next-gen console right away when the install base for the series x would be at its peak. Microsoft would have to give them a ridiculously good deal to make that happen, which is I guess within the realm of possibility, but again, would require a lot of coordination and a lot of risk on both sides.