I understand that there are only two options

In core Perl, yes (Update: actually, autovivification isn't even in the core). But choroba showed one possibility, and writing a single-purpose routine isn't difficult either (I've admittedly compacted it a bit):

use warnings;
use strict;

sub dive { my $r = shift;
    $r = ref $r eq 'HASH' && exists $$r{$_} ? $$r{$_} : return for @_;
    return $r }

use Test::More;

my $h = { a => { b => { c => { d => 'e' } } } };

is dive($h, qw/ a         /), $h->{a};
is dive($h, qw/ a b       /), $h->{a}{b};
is dive($h, qw/ a b c     /), $h->{a}{b}{c};
is dive($h, qw/ a b c d   /), 'e';
is dive($h, qw/ a b c d e /), undef;
is dive($h, qw/ a x       /), undef;
is dive($h, qw/ a b x     /), undef;
is dive($h, qw/ a x y     /), undef;
is dive($h, qw/ a b x y   /), undef;
is dive($h, qw/ x         /), undef;
is dive($h, qw/ x y       /), undef;
is dive($h, qw/ x y z     /), undef;

is_deeply $h, { a => { b => { c => { d => 'e' } } } };

done_testing;
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Update: Both of the links in your post appear to be broken. I assume you were trying to link to perl5280delta and RT#127712.