Not sure if its vanilla Minecraft that's giving too much copper but, I was in the ATM mining dimension and got almost a diamond chest worth of copper compared to other ores like iron I've gotten maybe 5 stacks of ore

Playing on version 0.2.20 at the moment cause server files are dicey right now

same issue in 0.2.29

i've got like two stacks of iron, and 15 stacks of copper

In vanilla minecraft copper ore drops 2-5 raw copper without fortune, vs iron, that just drops one without fortune. this means that the amount of copper should be higher, although this does seem excessive. Might be more about which levels being mined at in the mining dimension?
Iron is more abundant at lower levels https://twitter.com/henrikkniberg/status/1465721712973164544/photo/1