When you do `python -m pip install` you're going to get a version of pip that has the same idea of what its environment looks like as the python executable, which is what you want, and which isn't guaranteed with the the `pip` executable in your path.

As an aside, I disagree with the `python3` part... the `python3` name is a crutch that it's long past time to discard; if in 2025 just typing `python` gives you a python 2.x executable your workstation needs some serious updating and/or clean-up, and the sooner you find that out, the better.