Bitcoin Core is not a suitable example here as it doesn't use the concept of mnemonic recovery words. In core you could import descriptors based on a master private key (xpriv) which itself is derived from a set of mnemonic recovery words and an optional mnemonic passphrase.

Sometimes a pictures allows things to sink in better. What nc50lc is speaking of, you can find in the BIP32 Root Key Derivation


Source: https://raw.githubusercontent.com/EAWF/BTC-Toolbox/3938785f186c76598989cc0aa017ad351483d3b1/Images/KeyDerivationTechnicalOverview.png

So, wallets that do implement BIP39 without bugs should all derive the same Master Private Key from a same set of mnemonic recovery words and an optional mnemonic passphrase.

The devil may be in the details and I can't recall from the top of my head what BIP39 says about input sanitation (if any!) for the optional mnemonic passphrase. E.g. a trailing space should be perfectly valid, but what about two or more spaces? Are they sanitized to one space or not?

I did some experiments long time ago with Electrum but unfortunately can't recall the results either. What I remember was something surprises me... will need to repeat and document results better.