Preface: this is just how I do things. I learn on my own and where I say 'you' I mean 'me', so don't get offended if it appears like I am being patronizing. None of this might work for you, but if it helps you or someone else then it was worth writing. Let me know if anything is confusing.
Learn about environments. This is what is going to get you at first. You can't just 'pip install blah' whenever you need a library because installing one thing can break another thing without knowing it. So, you need to have a python where it is just for depthai and a python which is just for pytorch, etc. I use conda because it makes installing pytorch super easy, so I recommend that. But if you don't use conda learn to use another environment and make a new one everytime you want to try a new python thing.
Next, I would ignore trying to figure out what object oriented coding is, unless you are already familiar with it. You will figure it out one day, like 'oh, that's what that is, now I get it' just by trying to get things to work. But if you learn the definition and try to figure out what the hell it means and why you want it, you will probably just get frustrated.
The trick is to learn the basics and then find a somewhat simple but practical goal and make that your project. For instance I wanted to do object recognition and character parsing in real time using depthai, so I went through a few basic python lessons and then rewrote some of the examples in the depthai documentation. Find a simple demo and try to understand what it is doing, and then re-write it without copying it and try and get it to run. If it won't do what you want at least get it to a point in the program where it should be doing what you want and replace that with a 'print("this should be awesome")'. That way you can see little progress milestones and not be overwhelmed.
The most important thing about python in the very beginning is learning about how it handles types. Strings, dicts, lists, numbers, etc. These are not obvious especially because they are not declared, and they will break things easily without knowing why. You need to initialize every variable before trying to use it, so
if poop == healthyColor: print('looks like poop')
else: print('see a doctor')
before you do any of that you need to make sure you have
poop = ''
healthyColor = 'brown'
