I think you are not understanding how a texture is applied on relation to the UV of the model. On this gif I'm using a tileable brick texture with two examples: One where the model has some UV shells/islands/pieces with equal texel distribution (the UV's are scaled acording to the size of its polygons in the 3d space so…
Use a common strategy that actually works... Tiling normal maps for most of the structure, combined with detail geometry on the edges. For example: https://polycount.com/discussion/88996/my-work-at-pi/p1