This is an interesting question for me. The first question in my mind was, does "Yoroi" (for example) know my secret seed phrase when I create it? Is it stored somewhere in their servers?
Then I thought to myself, that would be outrageous, it should be generated randomly and only you can know it.
But then, I thought, how can Yoroi's "algorithm" (again using Yoroi for this example) create a seed phrase that is unique to a certain person without (I assume) knowing other seed phrases? (Since it cannot compare seed phrases because it doesn't know other people's seed phrases)
This applies also to other wallets when you create on their platform: Nami, Yoroi, ADALite, etc., etc. (Might be also applicable to other wallets like MetaMask, Phantom, or even Trezor and Ledger).
It's truly a very curious question. Thanks in advance!