Some people go for too much security, the security that will later let them lose their bitcoin. An example is someone that split his mnemonic into different parts, but later lost one the the parts. Some people will have many security layers so that the bitcoin wallet can not be accesssed by any other person, but later the person may find it too late and not able to access it or it will be in a way that his family will not be able to access it. Security is good but it should not be complicated.
You are very correct, some people simply complicate security that they will begin to struggle about it tomorrow.
For example; The splitting of seed phrase without knowing that they are introducing another failure point. That is a good idea if done correctly, but it can easily turn a bad idea if;
it is done for a long term purpose
if it is kept in more than two locations.
About introducing different layers of security. That is not a good security tip. In security, it should be simple but cannot be broken if tried and not so so complex to avoid being tried.