Multi vendor question

So i have 2 keys from.same company and looking to do a 3-2 multisig.

I wonder if I take the seed from one of them to another vendor later on make it more secure or should a new seed be created just for that vendor?

Also thinking of generating a seed as bip85 for easier to back up just in case. From what I know if the bip85 seed is used in a multi SIG one can not are tx if they don't have the descriptor