You will never look like a model by just lifting weights and running. You need a propper diet plan and a life that supports it.
Going on dinner with your friend? that will be a no for a year.
Having a bussiness lunch meeting with clients or bosses? Thats a no for a year.
Skipping a week or more of lifing because of unexpected life reasons? Thats a no for a year.
Guarantee a majority of your sleep to be of good quality for a whole year? Very few can do that.
Being on a caloric deficit and maintaining a high protein intake every day for a whole year? That is really hard and requires you to have no unplanned events for a whole year.
Getting in a situation where you have no real good options for your diet plan, you need to make sure never to get there for a year.
If your goal is "just" to loose weight its a bit easier but still a lot of hard work with no compromises for a year, and if you want to look like a model then you need hard work and good genetics to support that.
The time investment depends a whole lot on external factors and its never minimal.