I meant if you wrongly set up a valid address but you don't have a private key, or something like coin burn.
Is the only difference between these addresses is network byte?
No. Network byte is the distinguishing factor between different coins or mainnet/testnet. It affects the prefix of the address.
No. Bech32 in particular, only works for compressed public keys.
Bech32's address generation is particularly complicated (it involves extra steps after the RIPEMD160 hashing) and I don't think I'm the best person to explain it so I will leave it for someone else. The reference code is located here:
https://github.com/sipa/bech32/tree/master/ref.
P2PWSH is just like how a P2SH address is created except the fact that there's a witness program being wrapped inside the redeem script.
Small addition Can more than one valid address be generated from a private key?
Other than what BrewMaster mentioned, each private key can be be used to generate a compressed and uncompressed address which could in turn yield two different addresses.