I've a single signature wallet but I heard recently that the multi-signature wallet has more security and that interests me as my stored assets increases.
You can increase your security, if you create your multi-signature wallet in a correct way,.
If you are going to create a multi-signature wallet and keep all the seed phrase in one place, you won't increase your security.
Create your multi-signature wallet, if you know what exactly your are doing and don't forget to keep all seed phrases and master public keys is safe places.