I used to have an old Trezor One hardware wallet that I used for cold storage. I'm far from a techy but I found it pretty easy to setup and use. You basically are given 24 random words that you write down and keep securely. When the new Trezor Model T became available I decided to buy one since I thought it would offer better security, however, when I was setting up the Trezor Model T it would only give me a 12 word seed phrase, rather than the 24 I was expecting. I'm not very good at math but doesn't this mean that the new Trezor Model T is twice as easy to crack as the old version since only 12 words need to be guessed? Feels like a step back to me and it makes me a bit nervous.
According to this Wikipedia explanation, a 12 word seed phrase provides 128 bits security, which experts say is secure enough. A 12 word pass phrase is the same strength as most bitcoin private keys. https://en.bitcoin.it/wiki/Seed_phrase#Explanation
Splitting a 12 word passphrase is not really safe because it is far easier guess the other 6 words than it is to guess 12. For example, if it would currently take a million years for todays computers to randomly guess a 12 word passphrase, it doesn't mean that it would take only 500,000 years to guess a 6 word passphrase. If you split a 24 word passphrase and someone finds 12 words, it is still next to impossible to brute force the other 12. If you split 12 and someone finds 6 then you might be in trouble if they are knowledgeable enough. I would recommend you use the optional 13th word pass phrase for additional security.
in my opinion, multi signature is the safest, because even if someone finds your 12 or 24 word seed phrase, it won't be enough. they'll need 2 of 3 or 3 of 5 private keys. casa hodl offer a pretty good solution https://keys.casa/
I use a Ledger Nano S and it offers 24 words. Is there any way to change the Trezor Model T so that it offers 24 words.
If you want to recover a 24 word seed wallet on the Trezor Model T, you can do that but I don't think you can setup a new wallet with 24 words. The reason the original Trezor used 24 words was because there was no touchscreen and you had to recover a wallet by entering in the 24 words on your computer in a random order. Even if your computer was compromised and a keystroke logger got your 24 word seed, it would still be next to impossible to guess the correct order. If you want to recover a wallet with the Trezor Model T, there is a small screen that allows you to renter each word, which is much safer than typing anything on a PC or Mac. So basically the 12 word seed phrase on the Model T is just as safe as the original 24 word seed phrase Trezor.