Tom's Hardware - This chart sums up the situation with Core i9-10850K nicely: The stock Core i9-10850K and Core i9-10900K offer the same performance when calculated as an overall measure (geometric mean)
i3 10100 vs i5 10600K vs i7 10700K vs i9 10900K - YouTube
Intel 10th Gen Core i9-10900K and i5-10600K Review - PC Perspective