Converting the old world type to infinite in in 1.20.70 does not update the world to post 1.18 world. There is no extension of world hight. The new biomes don't generate and new items cannot be crafted, example the bamboo blocks. The world is stuck in 1.17. Also if you try to make world infinite pre 1.18 and then update to world height it leads to some empty or void chunks below y0.