How to check whether the fields of maketitle command is empty

As some people know,i insert tags for command maketitle and it fields ()@author,@date,thanks and title). All works ok,but for @thanks it show,that variable is empty,but it is not empty. I tryed to use tl_if_empty ctf|ntf|Ntf,but it fix this issue,but show not empty @author and @thanks,even if i haven’t it in my document. Help me please,how i can correct check,whether this variable empty. For example if i haven’t author,variable @author should be empty. Thanks everybody for the help.

documentclass{article}
usepackage{tagpdf}
tagpdfsetup{tabsorder=structure,uncompress,activate-all,add-new-tag=Title/P,interwordspace=true,tagunmarked=false,log/all}
pagestyle{empty}
ExplSyntaxOn
prop_set_from_keyval:Nn l__kozlovskiy_data_of_title_prop
  {
    @author = H1 ,
    @date   = H1 ,
    @thanks = H1 ,
    @title  = H1 ,
  }
  makeatletter
DeclareRobustCommandthanks[1]{footnotemark
    protected@xdeforig@@thanks{orig@@thanks
        protectfootnotetext[thec@footnote]{#1}}}
makeatother
cs_new_protected:Npn kozlovskiy_maketitle:
  {
    tagstructbegin{tag=Title}
prop_map_inline:Nn l__kozlovskiy_data_of_title_prop{
cs_set_eq:cc { orig@##1 } { ##1 }
tl_if_empty:cTF{##1}
{
use:c { orig@##1 }
}
{
cs_gset_protected:cpn { ##1 } {
tagstructbegin{tag=##2}
tagmcbegin{tag=##2}
use:c { orig@##1 } 
tagmcend
tagstructend
}
}
}
__kozlovskiy_original_maketitle:
    tagstructend
  }
cs_new_eq:NN __kozlovskiy_original_maketitle: maketitle
cs_gset_protected:Npn maketitle { kozlovskiy_maketitle: }
ExplSyntaxOff
%
author{alexandr Kozlovskiy}
date{today}
title{test document%
  thanks{Alexandr Kozlovskiy}
  }
begin{document}
tagstructbegin{tag=Document}
maketitle
tagstructbegin{tag=P}
tagmcbegin{tag=P}
Test
tagmcend
tagstructend
tagstructend
end{document}