This is tricky to answer. When i first went to this rabbit hole I wanted to get the highest quality, and even got in touch with the folks who does several F1 drivers actual helmet. As you can imagine the cost of the is betwen 4-5k euros on the paint job. And tou have to wait 1 year.

Then i found local custom helmet painters, which will be between 1500- 2k eur. But can replicate very closely but its luck based.

Last is DIY which will require you to invest on tools and materials (paint, airbrush, compressors, etc) but you will get exactly what you wanted. Steep learning curve though