I was going to suggest monopod, myself, and I see the OP is looking into it.
No you don’t. You can re-focus in-camera without using the other hand. I never have need for two hands when I’m focusing–unless I’m manually focusing for some reason (which is rare for me these days.) I do try not to shoot one-handed as two-handed gives me a little more control and it gets tiring shooting one-handed, but there are certainly times when I shoot one-handed, too, with little loss of control. Once your settings are dialed in, you don’t have to move them unless the lighting situation changes. Plus you can use something like A (aperture priority) mode, which pro photographers do use, too. Using the automatic settings and technology to your benefit in situations where it is helpful is something pros do.