Security is like an exponential thing, not like a sum, so if you add one or more layers of security, security level will be exponential and stronger. That's how a multisig wallet can secure your fund better but if possible, wallet software used to create wallets either single signature or multi signature must be strong and secure, in how it generate wallet seed phrase and have enough strong entropy.

If you already use a good wallet software like Electrum, to create single signature wallets with strong entropy, it's good. If you want to improve security, you can consider to create a multisig wallet with a same wallet software, Electrum.

Single or multi signature wallet, make sure back up your wallets, and test backups for recovery before using your wallet.
[Guide] Creating an Electrum multisig wallet.

WT?

How is this even possible?

Generating the keys separately and they would work normally?
Wonders shall never end, here I am thinking I've known what's needed to know.

Is there any video or tutorials about generating multisig separately and still make them work together normally? This is my first time hearing this, I thought it's only possible with single sig wallets.

Well, this is definitely not a stupid question. because it actually raises an important security question to think about which is the weakness in entropy. yes multisig can reduce certain risk, that would not mean that it automatically remove every weakness in the bitcoin key generation and storage.

weak entropy will definitely affect multisig, because multisig doesnt fix a wealky generated private key. let say for example in a 2-of -3 multisig wallet, if an attacher recovers one private key, they still need another key to spend the funds. this is one of the advantage if the multisig. however, if the attacker did much and was able to recover the two keys, then that's when they will be able to spend the coin. and that is more reason why each key is supposed to be generated securely with a very strong entropy and even using different device just to reduce the risk.

also i realize that miltisig has it own challenge that you must keep proper backups of your own keys and wallet configuration. because if you happen to lose too many keys, you may not get access to your funds, and also setting up and recovering a multisig wallet can also become more complicated than actually using a single signature wallet. but if you can do it right multisig will sure give more security than just a single key wallet.    

Yes bro. Imagine you have a 2 of 3 multisig setup and all of the keys are generated with weak entropy, it means that the attacker can brute force the key the same way it happened in colcard attack. Since all the keys are generated by weak entropy, the attacker just need repeat the process twice to get the second key. Just know that weakness is weakness, you can't have a weak foundation and expect the building to be strong, just because you used durable materials for the walls.

Weak entropy is weak entropy, either multisig or not I don't recommend keeping your Bitcoin on a wallet that's known to have weak entropy, avid them at all cost and generate a better one.

Although how severe it is depends on how many of your signing keys are compromised.
You can use roll dice to manually supply randomness.

Do not expect that a weakly generated entropy will become stronger if keep in Multisig, Multisig is not a weak seed fixer.

I hope I have understood your question correctly. What you perhaps may want to read is about the P2(W)SH methods to build transactions, which is the way multisig are built (P2TR - Taproot - also works but P2TR has some challenges to make it "more secure" than a regular single-signature P2(W)PKH transaction due to the so-called "key path").

As you probably know, the receiver of a Bitcoin transaction has to solve a mathematical challenge. The challenge for a regular P2(W)PKH tx is: "Provide the public Key corresponding to the address I stored in the transaction and then sign the coins with the private key associated with this public key".

In the case of P2WSH or the older P2SH, the challenge is different: "Provide a script which corresponds to the hash I stored in the transaction. If the script contains public keys, provide signatures for all private keys associated with it." (this is very simplified, there are also other kinds of scripts possible)

All these keys can be generated in the way you want, so you can use several different entropy sources (e.g. different Bitcoin wallet software) if you want -- you only have to be able to build the script, and then provide the hash of the script. And of course you need to know store the private keys somewhere (offline preferrably).

The nice effect Charles-Tim described is that the "redeem script" is not visible until the coins are spent. A hacker only sees there is a P2WSH transaction, he can't see if it's a multisig or some other kind of contract.

Yes, weak entropy can still affect multisig because how secure a multisig is depends on how strong the keys generated are. If the keys can easily be predicted by attacker's, then it becomes an issue.There are still problems that can occur even while using multisig.
Managing multisig can be complicated because there are so many things involved such as, the user will need to keep track of different keys, backups, which may be on different devices or different location making it to be tedious to the user. It is even possible to lose access to ones bitcoin if there is no proper recovery plan.
Therefore, multisig can provide good security but it all depends on how it is being done. Also how secure a wallet is does not depend only on the method of security used but if the method is properly used.

Yes. For example if you use a 15-of-15 multisig but use private keys 1 to 15 (the numbers) that is going to be the weakest multisig ever. Or if you use a broken code that produces a broken entropy then again it will be weak and can be broken and your coins can be stolen.

In other words if the entropy generation has a bug, then using multi-sig won't provide you with meaningful security.

If you create all the keys in one go on the same machine and store them in the same place and in the same manner. It is not so much a weakness but rather a pointlessness.

Multi-sig is useful if each key is produced separately and is kept separately. Otherwise there is not much point in it.

It's not actually a stupid question besides it is logical to be concerned about entropy these days especially based on how the previous hacks have been conducted by exploiting firmware flaws in entropy generation. The fact is entropy is as safe as you try to make it.

Regardless of using a multisig, I've come to discover that the safest way to seed generation is to use custom words In addition to your regular 12 word seed. The more random and non existent the word is, the stronger the entropy.