World is frozen in one tick for few socnds, then loads and freezes again

World became frozen, mobs did not move, particles and new items did not appear, hitting mobs did not do anything, I could not open inventory, HUD was frozen, too. However, world "un-freezed" for a second or two, then freeze again. Only one world is affected. Experimental caves and cliffs turned on. Device: Huawei i6 prime 2018