Though, with all the variables correct, it is still not working. -M command is working if it is between the opendir and closedir lines

Well you have  -M $moviedir[1] and  -M "$CosMovFolder/$moviedir[1]" its the basic stumbling block of readdir that everyone stumbles on .

readdir is just low level api ... low level api are a pain

use Path::Tiny its easy

use Path::Tiny qw/ path /;
my @sorted_files =  map  { $$_[1] }
                    sort { $$a[0] <=> $$b[0] }
                    map  { [ $_->stat->mtime, $_ ] }
                    path( $CosMovFolder )->realpath->children();
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