When I render out it keeps putting this in a small box. But if I select "Scale to fit" it makes it crappy resolution. What am I doing wrong? It was filmed on a hero7 in 4k.
Your settings are butchered! The Sequence - the quality that you are working with on the timeline - is SD meaning DV video at 720x480, then the Export is set to 1080 HD at 1920x1080, except the pixel aspect ought to be square (1.0) but is 1.2, everything is a mess.
Either edit in a Sequence to match the 4K source, then export as 1080p, or edit in a 1080p Sequence and Export to match