I think you need

use crsTools4 qq{$sth}; # import an EXPORT_OK var
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in the script. The package should probably be

our @EXPORT_OK  = qw($dbh $sth);
our ($dbh, $sth); # declare vars to be EXPORT_OKed
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and remove the our in the connect2db sub.

I don't know where $sth2 would come from.