Given the extremely short development timeframe (1-2 years from initial digital design to flying prototype) it's probably reasonable to assume that the 6th Gen prototype has re-used much of the internals (AESA, DAS, EODS and electronic warfare systems, sensor fusion etc.) developed for the F-35, and build upon this by further reducing the IR and airframe radar signature, likely adding two engines (Pratt & Whitney F135?) for greater speed and supercruise ability as well as adding 2D or 3D nozzles optimised enhanced A2A combat.
As such, it doesn't need to be a massive leap forward in what is already pretty impressive sensor fused tech in the F-35 and to a lesser extent the F-22, but it does need to be kinematically competitive (+F-22), be able to be produced quickly and affordable to be made in sufficient numbers to make a tangible difference in the balance of power.
For me, the real innovation is the impressively short concept/design to prototype timeline where the real competitive advantage lies. Better to rapidly innovate and pivot with incremental upgrades that quickly and tangibly enhance capability rather than the design philosophy/assumptions that underpinned the F-22 (the late-1980s) and F-35 (early C21's)