rhelmot: last one:

Loading lib/JSON.pm failed. No B module?
perl says : Can't load module B, dynamic loading not available in this perl.
  (You may need to build a new perl executable which either supports
  dynamic loading or has the B module statically linked into it.)
 at lib/JSON/backportPP.pm line 1527.
BEGIN failed--compilation aborted at /nix/store/rb2rzqpypp3rfv35v9fiy9sja0zr92lp-perl-x86_64-unknown-freebsd-5.42.0/lib/perl5/5.42.0/x86_64-linux/B.pm line 33.
Compilation failed in require at lib/JSON/backportPP.pm line 1527.
BEGIN failed--compilation aborted at lib/JSON/backportPP.pm line 1567.
Compilation failed in require at (eval 9) line 1.
BEGIN failed--compilation aborted at (eval 9) line 1.
 at (eval 8) line 1.
Compilation failed in require at (eval 8) line 1.
Setting environmental variable 'PERL_DL_NONLAZY' to 0 may help.
No Makefile created.
Welcome to JSON (v.4.10)
=============================

 ** BACKWARD INCOMPATIBILITY **

Since version 2.90, stringification (and string comparison) for
JSON::true and JSON::false has not been overloaded. It shouldn't
matter as long as you treat them as boolean values, but a code that
expects they are stringified as "true" or "false" doesn't work as
you have expected any more.

    if (JSON::true eq 'true') {  # now fails

    print "The result is  now."; # => The result is 1 now.

And now these boolean values don't inherit JSON::Boolean, either.
When you need to test a value is a JSON boolean value or not, use
JSON::is_bool function, instead of testing the value inherits
a particular boolean class or not.

Checking if your kit is complete...
Looks good
JSON 2.5 is required for $ENV{PERL_JSON_BACKEND} = 'JSON::backportPP'
 at /nix/store/rb2rzqpypp3rfv35v9fiy9sja0zr92lp-perl-x86_64-unknown-freebsd-5.42.0/lib/perl5/5.42.0/CPAN/Meta.pm line 616.