I also wonder if your Ubuntu system perl has patched the perl v5.34.0 security vulnerabilities described here.

Ubuntu Perl does apply CVE-related patches. Here's my list from 5.34, perl -V:

DEBPKG:CVE-2020-16156-1.patch - [PATCH] bugfix: signature verification
+ type CANNOT_VERIFY was not recognized
DEBPKG:CVE-2020-16156-2.patch - [PATCH] Add two new failure modes base
+d on cpan_path
DEBPKG:CVE-2020-16156-3.patch - [PATCH] use gpg --verify --output ... 
+to disentangle data and signature
DEBPKG:CVE-2020-16156-4.patch - [PATCH] replacing die with mydie in th
+ree spots
DEBPKG:CVE-2020-16156-5.patch - [PATCH] disambiguate the call to gpg -
+-output by adding --verify
DEBPKG:CVE-2020-16156-6.patch - [PATCH] s/gpg/$gpg/ in system, add quo
+tes where needed
DEBPKG:CVE-2020-16156-7.patch - [PATCH] s,/dev/null,$devnull,
DEBPKG:CVE-2023-31484.patch - [PATCH] Add verify_SSL=>1 to HTTP::Tiny 
+to verify https server identity
DEBPKG:CVE-2023-47038.patch - [PATCH 1/2] Fix read/write past buffer e
+nd: perl-security#140
DEBPKG:CVE-2022-48522.patch - [PATCH] Don't try to Sv[PI]V() on an und
+ef index SV in find_uninit_var()
[download]

...plus 50 non-CVE related patches.