But I can still spend 30.99 btc, right? If yes, I don't understand Electrum decision to exclude P2PK balances from the address balance!
Electrum is not excluding that balance, the block explorers you check are falsely displaying the P2PK balance as the P2PKH balance. Imagine if you had two checking account in bank A and bank B, you won't see your balance B when you check your A account and vice versa, even though both of them are your bank accounts and you spend from both using the same signature.
In Bitcoin you can create a lot of different addresses using the same key pair. 2x P2PK, 2x P2PKH, multiple P2SH with various scripts (eg. 1of1 multisig, locktime, conditionals, wrapped witness), 2x P2WPKH, multiple P2WSH with various scripts, multiple P2TR.
But when you create a wallet with that key, the wallet has to know which type of output script (or address) it needs to watch. So when you import your key and select the P2PKH address or import P2PKH address in a watch only wallet it will only watch the P2PKH outputs and report that balance. Which means everything else including P2PK outputs will be ignored.