What works for me is in between. I use both motivation and determination to achieve my goals, trying to use as little determination as is feasible. When I feel unmotivated, I don't try to fight it at first. If there's something else that's equally urgent but I am more motivated to do, I'll do that. If I'm just feeling sluggish overall, I'll go eat lunch or do a workout or drink a coffee or something. And once I don't have a choice but to will myself to do that thing, then I'll do that. Much of the time I don't need to because "resetting" myself will get me to that state of mind.