>>10144181. do learn uv mapping it's fundamental
2. you don't actually need uv's here, you could also use something called triplanar projection. this is also very useful so look it up.
as for imperfection maps there are some here that will help
https://www.artstation.com/marketplace/p/3yAy/free-surface-imperfections-pack
these do look quite extreme but you can do a lot by just manipulating them
pic-related is an example of such a setup where:
1. value node sets your base roughness value
2. the float curve allows you to manipulate the values in the roughness
3. the roughness map's values are then added on top of the base roughness (whiter = rougher)
the clamp is there for housekeeping
adding isn't the only operation. subtract, multiply, overlay, screen are all just as useful.
adding imperfections to roughness is just the start
you can plug scratchy looking ones into bump to add little scratches
you can use them to mix colour corrected version of diffuse maps together (e.g. the same scratch map in bump can be used to blend in a darker version of the diffuse colour in the scratched area)
have a play, i think you'll enjoy it. look up some tutorials on youtube to see how people use them.