When seeing errors (Bareword found where operator expected), try pre-loading the module before running parallel. See, this post.

use LWP::Simple;

# On the Windows platform, pre-loading essential modules
# (required at runtime) may be necessary for extra stability.

if ( $INC{'LWP/UserAgent.pm'} && !$INC{'Net/HTTP.pm'} ) {
   require IO::Handle;
   require Net::HTTP;
   require Net::HTTPS;
}

# run parallel

...
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