New submersible water pump has rust
Perfectly normal for non-stainless steel pumps to rust.
Even stainless steel ones may rust, slightly.
The white corrosion may indicate some cast aluminum components, and if so, the combination of aluminum and iron components would also tend to promote galvanic corrosion.
It's not a cause for great concern - it's primarily cosmetic. It does lead me personally towards choosing stainless steel pumps, but cast iron pumps that look awful will work for a long time, looking awful. They do become difficult or impossible to disassemble eventually, but that's over a fairly long lifetime.