for now i do c++ for tick based and bp for event based things
In most cases: Don’t worry about performance, and do whatever is cleaner, more maintainable, more scalable.
If you are concerned about your project’s performance, you should start by profiling. Unreal provides a tool called “Unreal Insights” exactly for this purpose. Usually, if you worry about optimizing code without profiling and checking what’s the current bottleneck of your game, you’ll end up with 0 performance gains. For example, if your bottleneck is the GPU or graphics (which is the case in many scenarios), you’ll notice that making small tweaks to code will affect CPU usage but it’s irrelevant for your game FPSs which will stay the same.
Here are some docs to get you started on Unreal Insights and performance profiling:
Intro to Performance and Profiling: Performance and Profiling Overview | Unreal Engine 4.27 Documentation | Epic Developer Community
Intro to Unreal Insights: Unreal Insights in Unreal Engine | Unreal Engine 5.3 Documentation | Epic Developer Community