Importing Seed Phrases .... whats stopping somebody from guessing correct phrases?

Alright team, what am I missing? I have learned A LOT about Crypto/ETH specifically in the last few months (all good news) but I come from a long line of IT/Computer/Engineering and I have questions.

First, Finally got some test ETH on a wallet, with the ultimate goal of moving all my ETH off the market and placing half in cold storage and half on a validator. Before I do any of that, I am testing the waters with ETH transactions and how they work so when I go to transfer the guts I wont risk losing... a lot of money.

So this question comes up when I created a wallet in chrome with metamask. I got my seed phrase (wrote it down, etc) and then transfered .01 ETH from my exchange to my metamask wallet. Perfect, exactly as expected.

So now to continue my learning, I want to now get the same wallet on my phone for viewing purposes, etc. Lo an behold, I open up MetaMask on mobile, click "import from see phrase" and literly type the seed phrase into my phone and BOOM, instant access to my wallet (with the ETH)

So, looking at these 12 key pass phrases... like what is stopping people from just guessing a valid wallet pass phrase? Its literlly 12 dictionary words in random order; there is a good chance SOMEBODY (i.e. a computer) can guess SOMETHING valid over time. And if they do, they are instantly in.

So my final question is this, do all wallets generate key phrases differently? How does the underlying wallet stay unique? If I buy a Lattice1 wallet, can I import my meta mask account to it with the seed phrase? (I do not want to do this, just want to know if they wallets are all interchangeable) I got tones of questions guys, please help me out here. Do all the different wallets have wallet addresses pre-assigned and does it directly pick based off key phrase? Who is deciding my wallet address? the wallet company or the seed phrase?