Hi,
I had the same problems with my GoPro Black 3+.
I also have two, exactly the same versions. The first Blk 3+ worked and works just fine. Always ready to record, download, delete files, change settings, etc.
The second one I bought worked for a while then started the freezing issue.
I found that taking out the battery for a while (2-5 minutes) would sometimes allow me to change settings and delete files, etc. Or something silly like START RECORDING!
so aggravating! Later when that would not work, a combination of removing the memory and battery seemed to work. However this was only a temporary work-around and eventually nothing worked. By now I could no longer return it to where I bought it.
Furious, I finally ended up calling Go Pro and the person who helped me had me switch the chip with the one I was using on the original camera. When that did not work, he decided it was the camera not the chip and had me send the camera back directly to them at GoPro, emailing me a FedEx slip. So it seems the chip could be an issue and is something you should try if you can.
Not sure if that helps you but that was my experience.
Maybe I should make a vlog about it...