I had a similar problem where my moto G7 would not charge unless turned off, what I did was look at all apps that I had installed recently and either uninstall them or force stop them to see if it might be a software issue. Then I tried lots of different cables, and lightly twisted them while they were inside. Eventually, one of them must have dislodged some kind of dust particle or piece of lint and then it worked again. I would recommend getting a small canister of compressed air to have to hand to help clean the charge port periodically. Also make sure that you have all software updates up to date, just incase it is a software issue.