Hello. I have a lot of duplicate pages and the main page on my site, who knows how to help.
Home page examples: https://padabo.ru/, https://padabo.ru, https://padabo.ru/?ref=xranks, https://padabo.ru/? Yandex webmaster writes 159 duplicate pages. More examples /blog/home, /blog/. All categories open with a slash / and without a slash and many other duplicate pages 

I am not sure, but web.com and web.com/ should be solved via config.php and .htaccess configuration.
Not sure about the others, for me it looks to be fine to be able to set parameters.