Water Supply for Icemaker and water

Son purchased an older home and it had a brass line feed for the icemaker. We want to update this to have a valve box located in the wall behind the refrigerator.

My question is: the house has galvanized pipe and am assuming we can use copper for the line down the wall from the attic. How can I connect this supply line to existing galvanized pipe?

Or what is correct way to handle, dont think old saddle valve is best way to continue.

Thoughts?

I know many who have connected a saddle valve to galvanized, but only in an area where if a leak was to occur, it would not cause any damage, like outside adjacent to the spigot.

my best advice is to find copper and run a valve from there is there any copper in house

you can make a connection between galvi and copper with a dielectric union or a brass nipple between the two.