btcrecover does support brute forcing passphrases if you have the valid seed phrase, for both BIP39 and Electrum wallets. You can also do it with an address database looking for any used addresses if you don't know the master public key or any of the receiving addresses within the passphrased wallet. There are some basic instructions here: https://btcrecover.readthedocs.io/en/latest/TUTORIAL/#bip-39-passphrases-electrum-extra-words. There are also some example commands available here: https://btcrecover.readthedocs.io/en/latest/Usage_Examples/basic_password_recoveries/#bip39-passphrase-protected-wallets-electrum-extra-words

That is correct. Hardware wallets such as Trezor and Ledger both have a character limit on passphrases (50 and 100 characters respectively last I checked), but Electrum sets no limit, so the only limit would be the input limit for HMAC-SHA512 (or, in reality, how long a passphrase your computer can handle before it freezes).