my (@sargs) = @_; and my @sargs = @_; are equivalent.

my $config = {"delete" => 0, soFiles => []}; is a scalar variable holding a reference to a hash-table with two elements.  my %config = ( "delete" => 0, soFiles => [] ); indeed constructs a "classic" hash-table.

my $config = {"delete" => 0, soFiles => };
my $config = {"delete" => 0, "soFiles" => };
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are equivalent as the => automatically quotes its lefthand argument.

You must indeed use $config->{delete} = 1; as $config holds a reference to the hash.