Sorento, Tucson and Santa Fe PHEVs share a similar AWD system. The center differential can likely send more power to the rear than the R4P rear motor can provide, depending on the conditions and mode selected. This is typical of many mainstream crossover AWD systems with clutches or other slip limiting systems controlling power front to back. R4P is pretty limited on rear axle power, but even so, an electric motor provides plenty of torque at low speeds to get you going and keep you going on most slippery roads. Most would not notice the difference.

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Also like most systems in sedans and crossovers, including the R4P, I am pretty sure Hyundai and Kia also use traction control braking as the slip limiting system to shift power side-to-side on each axle. This is the least expensive and generally least effective method, but can still work pretty well in many situations. So, I doubt either system is significantly better than the other for most people, at least on paper.

There are more advanced AWD systems for frequent drivers of unplowed rural areas, icy hills, major off-road trails, etc. Toyotas with Dynamic Torque Vectoring also have a real limited slip differential in back, allowing better control of power on the rear axle. Some vehicles have such a system on the front differential as well, often allowing the vehicle to proactively send more power to any individual wheel with traction, rather than relying upon the reactive braking system to brake a spinning wheel and send limited power to the other side.

If you want a PHEV with a true off-road system, Wrangler 4xe Rubicon is your best bet by far. Or just go with a Rivian. An electric motor on each wheel offers amazing torque at zero RPM and superior control if the software is equally good.

All that said, Kia and Hyundai crossovers have improved a lot in recent generations. I think they are worth a look if you can get one. They probably have the same supply and markup issues, though. I've found some recent crossovers to suffer from lag in the double clutch transmission when selecting gears and they tended to have a harsher ride. I've heard the ICE comes on randomly more often than in Primes for no apparent reason. Minor things for most, really. I think the Sorento is pretty sharp and would have considered one had it been available to drive first.