Please see https://xyproblem.info/ and let us know what you're actually planning to do.

The modules are typically closed, and implement quite a lot of interfaces that you can use to customize their behavior. In many cases, invasive operations like in 6.x are no longer necessary. There might be a few cases where they are still necessary, but it should be the last resort, not the first choice.

7.2 is extended in a totally different way than 6.2, and you should embrace the new way as much as possible, rather than trying to bring the same techniques forward just because you used them in the past.