Ordinals are a waste of block space but what can we do? miners just want profits and they'll mine blocks irrespective of what they contain.
Technically it isn't a waste in block space. It doesn't take the space from actual Bitcoin transactions.
It's obviously wrong, Ordinals TX has size more than 0.
Ordinals NFTs reside in the part of the block where witness data resides. They are prunable.
Aside from prune node which only store latest blocks, you still need to store UTXO created by Ordinals inscription. Ordinals (mainly BRC-20) popularity massive increase total UTXO where it already impact IBD (initial block download) speed for Raspberry Pi and other device with <= 8GB of RAM.