2017 subaru legacy having power issues

[Ajfreeman.47]

My wife's 2017 subaru legacy has been having issues. One day the car is running fine and then the next it won't start. It started off with starting rough every once and while and I assumed it was just the cold. But then out of no where the car would have power but wouldn't start and a check engine light was on. It said it was a bad camshaft sensor so I replaced it and it fixed the issue and then about a week or 2 later it started having issues with the power where I would put the key in and then I would lose all power completely. The battery wasn't low or anything it still had full power. It just wasn't sending it to the car. So I took the battery post off and then put them back on and the power was back. I checked all the fuses and nothing is popping. I'm just not sure what is going on and I'm wondering if anyone else has had the same issue and if they know how to fix it. 2 days ago it started again hard and then I guess she said it smelt like a burning smell and then went away. Now it's running fine but im assuming it's gonna happen again. Does anyone know what the issue could be?