Does having the “www” matter for SEO purposes? I’d be surprised if it does. It’s mostly a historical thing, as I understand it, which is why most webservers don’t bother with it these days.
In that case, your best bet is to read the documentation for the plugin you’ve installed. Maybe email the creators of the plugin directly if you can’t find what you’re looking for.
Unfortunately there are tons of plugins, and this isn’t a WordPress forum. So you’re unlikely to find anyone that has an answer for you here.
This is coming from a time when we were running different kinds of servers like FTP servers. Today you are dealing to almost 100% with web services.
On top, in the head request to https://example.com there will be a “Location”-key with the value https://www.example.com anyway, so you don’t have to specify this in the URL.