14 meters isn't all that shallow. You have a nice amount of space. It sounds like your main problem is how to make it interesting, a flat expanse of nothing is very boring.
Even though it is a nice house and there are trees around the edge, all that flat grass monoculture, is a boring waste of space, unless you happen to need a soccer field.
So to start with think about things you might like to do with your front yard, and to grow in it. Would it be nice to have a little seating area to sit with a book and look over the fields? Would you like to attract birds? I presume there are front windows that look out over the yard. Think about the view from the windows and what you would like it to look like. Do you like flowers? Any particular kinds?
Look for pictures that inspire you.
Start by putting in hardscape, like walkways to the front door, etc. Choose materials carefully because you will be stuck with them for a long time. You want something that goes with the style of your house and the style of the garden you would like (e.g. loose, informal, rustic vs formal and structured).
This would be the time to think about arches, arbors, benches, fountain, paths to any of that.
Then you would do trees and shrubbery. You want a gradual transition from grass/ low flowers, to shrubs, to trees. If you do the trees and shrubbery mostly along the the sides that will balance the proportions.
Think about maybe sinking a little pond /water feature at one point, and building up a mound planting island somewhere else to counteract the flatness. Put some things in big containers.
Think about your front yard as several different areas/ spaces / rooms and plan it so you can't see it all in a glance and some things are hidden.
just some ideas to get you started!
(And remember this is a project that will go on for a long time and just get more beautiful each year. Be patient!)