I play guitar too. I was where you are at too when I started as I only played guitar with a pick so my right hand was just out of control.
I played the Banjo 103 lesson over and over and over again for a week or 10 days (I don’t want to remember!) Luckily I live alone because my practice just sounded terrible. But eventually I could get my fingers to more or less (often less) go where I thought they were going.
Unless you are naturally talented, it’s going to take some time for your fingers to learn. I had picked up the mandolin just before I started to learn banjo and found it pretty easy to get at least musical sounds out of it. But the banjo…!
Like most beginners, I thought I was going to pick it up pretty easily. But I found that right hand picking was really, really difficult. I practice a lot and only after about 7 months did I start feeling less uncomfortable about playing. I am three years in now and am just starting to feel like I am getting a handle on the instrument. And I didn’t even have to work much with my left hand so I cannot imagine how difficult it must be for those who have never played fretted instruments before.
So be patient. Practice a lot. A lot of it is about muscle memory and that just takes (at least for me) a long time.