Multisig is secured even if you have the keys for both of them. Just make sure that you generate the keys on different devices, not on the same device or doing it on an offline machine, and test it first with a small amount to make sure you have full control of your wallet.

The only drawback to using multisigs is that the transaction fees are not as cheap as a single signature wallet because multisig generates more size.

As pointed by BitMaxz, keys must be generated separately. Second, backups must be kept in separate locations. The reason being is that if keys are generated from a single wallet or device and it's compromised, multi-sig is pointless. Second, in case somebody barges into your room or house and all your backups are kept there, the security offered by multi-sig is also pointless.

Anyway, are you afraid that "someone randomly guesses one of your seed words"? I think that doesn't pose a threat. Anybody can get access to the complete list of the words used in BIP-39 seed recovery, for example, but good luck to them finding the perfect combination.

How much do you hodl, by the way? Or are you hodling other people's funds? I'm wondering, perhaps a passphrase will boost your security sufficiently.

On the one hand, Multi sig provides better security than single signature transactions, on the other hand, there is a risk of losing access if one of the keys is lost. Storing private keys in different locations can increase security, but you also need to keep your keys safe so you don't lose access to your wallet. Everyone has their own way of managing asset security, but the easiest way is not necessarily the most reliable. I agree with what @EL MOHA suggested to choose 2-of-3 to minimize the risk of losing access to the wallet.