This is about learning. I will buy a charge controller as like you say, they are inexpensive, and they do have a good amount of info on readout.
Just wondering for the sake of wondering and learning. The charge controller bucks and boosts, so I just drew the conclusion of using a buck/boost.
I suspect it may limit current based on battery type, which isn't native option on the standardish hobby grade buck/boost converters I have in mind.