Hey
@Nlake13, welcome to the forum!
There is not enough info in your description to be able to say much about what might be happening. I will point to a few things in your post though...
If the motors (without props on!) do not spin up properly in the Motors tab of Betaflight, then there is likely a problem that will keep you from flying successfully.
There are 3 flight modes and the default "acro" mode does not level itself, are you sure you have set it up to be in "angle" or "horizon" mode which do try to level itself?
You will need all 4 motors working to fly, and the motors will all spin at different speeds when flying, that is how it works, if one side is lower than the other those motors will spin faster to try and compensate so that is likely not your issue. There is also a thing called "air mode" where the motors will spin up faster even without throttle input, so air mode may be on also.
You may want to create a Youtube account, take a short video of each of the motors spinning (only to about half throttle, it is not a great idea to spin them any faster) and upload it to youtube and then post the link here so we can go watch it.
There is a lot to this hobby knowledge wise that you will need to understand to get things right, we can try to help but will need more info than you have provided in your post. If one of the motors no longer works correctly it is likely the 4in1 ESC is damaged, the video will help us to help you. I would guess that Betaflight configuration is 99% of your problems but that one motor is probably a hardware issue.