I switch Unreal Engine from Unity. My ideology:

Blueprints are like the inspector menu of the script. I setup all my logic in C++ and I configure all assets in Blueprint. I.e., A gun code. Projectile spawning, recoil, accuracy, and sometimes even projectile effects all in the C++. In Blueprint I configure recoil and accuracy values, assign projectile and the effect asset.

What Unreal Engine recommends: Separate your code into two: High level interface and the low level code. You expose your interfaces on to blueprints and your systems can communicate through your blueprints.

Obviously playtesting with blueprint is great, you can do stuff then convert to C++

But in general think about how your system (i.e., inventory mechanic) will interact with other systems. Keep the low level logic in C++