Get a sample from the garage door company

Either buy a Color Muse or hire a color consultant/color strategist who has one and works with color data values. Buy a Color Muse from Sherwin-Williams, The Home Depot, order by 10 am from Amazon and get it the same day (Prime).

You can measure the color of the door and find the closest color match possible in whatever paint brand you want to use.

Of course, you will have to get a large chip/sample and test in place to make sure it looks good.