Glad to hear it worked out. I just wanted to add that backticks, unless properly used, can very easily introduce security holes, which I wrote about here, where I also show some alternatives. In this case, since you want to also capture STDERR, I might recommend IPC::Run3. You should also be able to unset that environment variable using delete $ENV{LD_LIBRARY_PATH} instead of the unset command, and if you want that change to only be temporary while you run the command, you can use { delete local $ENV{LD_LIBRARY_PATH}; run_command_here }.

use IPC::Run3 'run3';

my @command = ('/path/to/python3.7','/path/to/script.py');

my $ret = do {
    delete local $ENV{LD_LIBRARY_PATH};
    my $r;
    run3 \@command, undef, \$r, \$r or die "run3 failed";
    die "command failed, \$?=$?" if $?;
    $r };
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