Is it correct to inherit a class from a singleton?

Question

PHP

Is inheritance from a class with a singleton a correct and competent solution? If not, why not?

Answer 1

If not, why not?

Because in the vast majority of cases singleton is not needed in principle. Avoid using this design pattern whenever possible.
I suspect that in this way you want to provide global access to things like access to the database and so on - there are other more correct solutions for this.
And inheriting from the singleton class is not correct, at least from the point of view of LSP (Liskov Substitution Principle)