You can read about the ICU issue at Android app size and lib_FoundationICU.so. I'm afraid there hasn't been much progress on this front, and short of being able to externalize the ICU data files and "thin" them out with some bespoke tool, I don't know if there is any other realistic solution.
As for the Foundation transitive dependency, @madsodgaard has been doing great work (see The adoption of `import FoundationEssentials` throughout the package ecosystem). It's a bit of a whack-a-mole scenario, though, since any one transitive dependency that does import Foundation will trigger the size inflation.