Electrum is a unique seed (segwit as default), it works for electrum wallet only, you don't need to keep the derivation path also, it could make you confusing in the future. Just keep the 12 seeds you will save.

cryptosteel capsule - It's able to keep full letter 12-word mnemonic seed, if you hold 24 seed, it will keep 4 letter front because of not enough space.
My point here is you don't have enough space to keep XPRV also on cryptosteel.