My apologies for the perhaps basic question, but I have searched and cannot seem to find an answer.

Up until now I have only used Ledger Nano S devices to store my Bitcoin and hold my private keys. I keep the recovery seed phrases for these secure.

However for the first time I have now also created a brain wallet. Whilst I do not intend to use it for the moment, I feel it is good practice to already have it in place now with a secure pass phrase that I have committed to memory. In the event of an unforeseen event or emergency in the future, I already have the Public Key to send to and have the ability to re-generate the private keys using the memory committed 12 word passphrase.

My question is, which wallet is the best in an emergency to recover this seed phrase to? It is a unique phrase that I created with the BIP39 tool (offline) and only has 12 words, though they are unique and memorable to me. My concern is the words don’t conform to the English BIP39 standard words and as such can’t be restored into wallets like Electrum or my Ledger devices.

Is anyone able to advise wallet services where one can restore a truly unique 12 word passphrase that wasn’t generated by a wallet service?

Or am I going about this the wrong way and in the event of recovery, simply generate the Private keys using the BIP39 tool and then use the private keys themselves in a wallet to restore?

Again, sorry for the basic question!