Camera resolution is locked and unsure how to fix

I probably ticked or changed some setting months ago, and now the camera is locked at what looks like a lower resolution or something? You can see when I take a screenshot the pixels are large and blurred, importantly it is ONLY the cameras that are locked, any UI/widgets are the correct 1920x1080 resolution. Sorry as I cannot give more information I have literally no idea how I did this lol.