I hate the door design on my laminate kitchen cabinets, how can I upda

If the back side of the door is flat with out the detail... just flip them around... you might need to fill in holes if they have the European style of hinges... but that is more labor intensive than dollar intensive... move the hinges to the other side of the door, sand, prime, and paint... just be sure to label each door so you know exactly which cabinet it fits

Are you looking for a certain style or cut?

change out the hardware, that will give it a different appearance

On a limited budget, there is not much else you can do except paint.

Those look like Thermafoil cabinets which is vinyl over MDF, the design is routed into the MDF. So maybe, you could buy some real wood veneer and glue it on and route the edges, then stain. or you could buy cheap masonite and glue boards over top, route the edge, and paint.

Or you could just order new doors. or make a totally new door from birch front plywood

You would need to remove the vinyl first.... https://www.youtube.com/watch?v=7w4Uxewfmb8&t=50s

I'd cut some thin mdf panels (maybe even wall lining boards for a not too plain look) to an even size to cover each rebate section making the top staight like the bottom. Leave edges square or you can bevel. Attach to each door to create raised panel doors. Fill joins and paint or decorate as desired either uniquely or to match the doors.

I believe my cabinet doors are very similar, but they are wood grain. I want to paint mine! If you can sand or use mineral spirits to remove your current paint, you will have a new surface to work with. You can remove the centers out of some doors and back the holes with metallic grates or chicken wire. You can glue mirrors or decals to the centers. You can paint ivy or morning glory vines around the edges and add flowers. You can paint Unicorn SPiT scenery on each center. You can remove all the doors and hardware and have all open shelving. Or you can stencil all your favorite kitchen designs on the fronts and frames, then distress all the edges, add larger vertical handles, and repaint the walls. Best wishes ☺️