[nesting maps] would be quite hard for n levels where n is determined at runtime

That's what Algorithm::Loops 'NestedLoops' is for. And (because I need to practice using it) the solution corresponding to yours would be

use Algorithm::Loops 'NestedLoops';

my @hosts = NestedLoops([([1..254])x2], sub { "192.168.$_[0].$_[1]" })
+;
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