It would be cool to see 16 CPU cores but I think 8 cores will still be "good enough", I think they'd either save money, put that ~70mm^2 (whatever it'll be) to extra GPU which could be another 24-32 CUs or combine both. If it is 2027 that's at worst Zen 5 but probably Zen 6, AMD will keep increasing clocks so 8x Zen 6 cores, 4.5GHz is possible
[1]. Even with reduced caches/other cost tradeoffs the uplift from current 3.5/3.6-3.8GHz (PS5/XSS/X) reduced cache Zen 2 to 4.5GHz Zen 6 will be big, Zen 4's already >1.3x IPC vs Zen 2. With similar IPC increases to Zen 4 and 4.5GHz that's circa 2x 1T performance, add in AVX 512, maybe some dedicated accelerators and other new goodies that's a good improvement.
4.5GHz because ~0.75x of the desktop's clock for efficiency reasons, PS5 is 3.5GHz, or 77.8% of the 3800X's 4.5GHz. For the rest of the system maybe 72-80CUs RDNA 5, 3GHz+ core (assuming AMD hit >4GHz desktop), 32GB GDDR7, 28-32Gbit/s 256 bit bus (896-1024GB/s), larger focus on RT and liberal use of "AI", "Neural" or equivalents in marketing material