You've misunderstood something. There is a 19 week gap between patches, but that is not the case between the 7.5 and 8.0. The gap between that is actually 8 months, because 7.5 is split into two halves so they have more time to work on the expansion. This has been the case prior to both Endwalker and Dawntrail, where the gap was increased from 5 months to 8 months.
- 7.4 23rd December 2025 (19 weeks)
- 7.5 5th May 2026 (19 weeks)
- 7.55 18th August 2026 (15 weeks)
- 8.0 2nd February 2027 (24 weeks)
Although there are normally 19-20 weeks between patches, it's a bit different for 7.55 and 8.0, but if you move the 4 over to the 15 weeks you get the same overall result.
Now, maybe they will try to put in a lot of effort and make it sooner than that. But how sooner? They might manage November 2026 again like they did with Endwalker. But to get it out in August 2026 would be some sort of big demonstration of how many more people they have employed to work on FFXIV.