There are situations where 60fps might be beneficial, but for most use as a dashcam, 30 fps is perfectly adequate and 4K is a clear benefit in many situations.
If you just want to make your videos smoother, you could try using an editor that will interpolate from 30 to 60 fps, that can produce some very nice video, although most software that attempts to do it struggles a bit with fast moving dashcam footage.
There are situations where 60fps might be beneficial, but for most use as a dashcam, 30 fps is perfectly adequate and 4K is a clear benefit in many situations.
If you just want to make your videos smoother, you could try using an editor that will interpolate from 30 to 60 fps, that can produce some very nice video, although most software that attempts to do it struggles a bit with fast moving dashcam footage.