Hi Pjotr,
can you describe your workflow step by step? It could be several issues here.
The blurry faces are probably caused by too large triangles - there’s a setting for that: Large Triangel Removal Threshold. But I’m afraid that if you change the geometry of a model too much, the texture will not look like you want it to. You’d probably need to use an external tool and paint textures from individual images onto your desired surface…