Hello
Unfortunately, your method is not working properly.
When applied, not only the widget title but also the entire content of the widget goes to the H4 header tag.
And by the way, formatting the widget titles in the footer with the H2 header in 2020 is a bit embarrassing for the author of the theme. I am asking for help on the website mocdysleksji.pl and on the website in the preparation of dzielak.com.pl.
Pozdrawiam
Arkadiusz Dziełak