2027H2 is my expectation as well; 2027H2 could still be in December 31, 2027 tho, or CES 2028 altogether. I heard that like 5 new (memory) fabs are being built right now, maybe it could help to reduce the shortages by that time.
A reliable leaker claims that Nvidia's next-gen GPUs, the RTX 60 series lineup, will be based on the Rubin architecture and are set to launch in the second half of next year.