Same passphrase for Hardware Wallets?

I am planning on using a multi-sig setup, please no debate on multi sig wallets,from what I read, this method is suitable for people storing around $500k+ , which is what I will be storing, in my late 20s , so this is a longterm thing. I have very good organization skills. My question is, I have purchased around 5 hardware wallets, and all will have the same passphrase. None of the hardware wallets from what I research, store the passphrase. Can I use the same passphrase for all of them? I cannot see much of the risk of it, as all the hardware wallets have different seedphrases.

My reasoning behind using multi sig, is the increased security, especially not depending on one hardware provider, for security, instead I will spread the risk to 5 different hardware providers. Am i correct to think, even if several hardware providers became all corrupt at the same time, they will still need all 5 hardware wallets in the multisig, in the correct sequence to recreate the multisig wallet, or they will at least need the multisig wallet file, plus 3 - 5 multisig wallets (i will be using 5-3).

Hopefully this won't turn into a discussion on why multi sig isn't needed for MOST people, i really just want to learn from people who understand the mechanics of a multi sig wallet.