I guess we will all find out soon if Pioneer is going to release a 4K UHD Blu-ray player! And they will have a model that will match what has been produced by Oppo.
https://www.whathifi.com/news/pioneer-to-fill-4k-ultra-hd-blu-ray-player-gap-left-oppo
https://www.whathifi.com/news/pioneer-to-fill-4k-ultra-hd-blu-ray-player-gap-left-oppo