Database Singleton or Dependency Injection?

Question

PHP

Actually, which is better to use? Both options work, but which one is better? Thanks in advance.
PS There is a Database class (select, update, etc.). And there is a User class that uses methods from the Database class.

Answer 1

DI, for tests

Answer 2

ST is generally recognized as an anti-pattern in PHP, firstly we do not test it, and secondly it is static.
In the case of a database, it will also not allow you to connect to more than 1 database / storage.
If religion does not allow DI, use registry, this is also badly tested, but in any case there will be no static database object.