A 3D Ship/Tech Artist Hans Palm has shared a couple of blueprints that can save you tons of time.
First of all, there is a minimalistic method to do triplanar mapping exclusively in UV space. The model has some downsides and limitations, but it is super fast for certain things. Simply paste into a new Material Function to use.
The artist used this method for the grunge and the Stars & Stripes skin in this work:
Then, there is a version of the artist’s cheap triplanar solution that includes a corrected normal map pass. He recommends using this version if you really need the normal map. Paste into a new Material Function.