I think applying design patterns blindly without understanding what problems they’re supposed to solve is often more harmful than not using them. It can lead to difficult to manage code bases because the program is over engineered for problems that don’t exist.
My general rule of thumb is to write code that can be easily adapted to unexpected changes in requirements. Avoid writing code that paints yourself into a corner. Simple solutions are often easier to work with than complex solutions. If what you’re doing adds a lot of complexity, take a step back and seek other options. Maybe you’re overlooking an obviously simple solution to the problem?
I think inheritance almost always has this “painting yourself into the corner” tendency. Once the design is set, it’s often difficult to break free from it. Composition along with interfaces is generally the better choice. Often not even interfaces are needed.
This comes with experience. You learn what works, and what doesn’t. Often you do it the hard way.
Databases are tricky. I have no good advice for that.
Haven’t properly watched the videos, but I don’t think OOP is that bad. I even think encapsulation is one of the core strengths of OOP.
I’ve worked with systems where no thought was put into encapsulation, and those are often incredibly difficult to work with because everything is heavily interconnected. Can’t make a change in a small thing without risking breaking something else at the other side of the program.
I like to see encapsulation as a workspace. It defines the tools we have direct access to. Changing one thing in a workspace shouldn’t affect anything on the other side of the program. Makes it much easier to collaborate in large teams. Minimizes the risk of interfering each other’s work.