How Do You Deal with Players Who Always Use the Same Opening?

Hi everyone! 👋
I'm a 13-year-old player and I’ve been playing on the site for a few months now. I’ve noticed that some players always start with the same opening moves (like or ) – and they know a lot of follow-up lines really well.

What do you usually do in that situation?
Should I also focus on learning one opening really well?
Or is it better to play something unexpected to break their rhythm?

If you have any tips, videos, or favorite openings for this kind of situation – I’d really appreciate it!
Thanks in advance 😊

Learn basic opening principles, which your opponent probably implements with their standard set-up. The purpose of the opening is to reach a playable middle game.
There, you are losing because you miss basic tactics. That's where your study should concentrate.