I've seen that as well, which pretty much assumes that it doesn't have the additional overclocking headroom we expected it to have but indications are that it STILL has somewhat lower temps than 8700k at the stock configuration, or overclocked. It's just that it's not offering the sort of benefits that delidding offers, which is what the overclocking community expected because that's what we saw on the last generation that had soldered TIM, which was some of the Ivy bridge CPUs.
Also, the 212 is definitely not the best performance for the price. In most regions, if you HAVE to use a lower end budget cooler, the Deepcool Gammaxx 400 is generally about five bucks cheaper, AND outperforms the Hyper 212 Evo somewhat.
Doesn't even need to be a big cooler particularly unless you are overclocking. The Cryorig H5, Thermalright Macho rev.B or Noctua NH-U14S are all capable enough for that CPU easily, with single finstacks and single fans. Overclocked to any significant degree, you'd want a twin finstack, twin fan cooler or water cooling whether AIO CLC or custom loop.