In gnc:html-document-render there is no way to suppress the title, (if (title)) is always true.
Why is that a problem?
I came across it when writing the tests for it https://github.com/Gnucash/gnucash/pull/391 I see that the html doc renderer is designed to check if title (and btw: also header) shall be set or not. But these checks are implemented in a way that is these fields will always be included, there is no way to create a condition, that these checks will prevent adding these fields (at least I did not find one up to now). So I added a test as "expected to fail" to the set of tests with a reference to this bug (not yet uploaded to PR#391).
A solution proposal is covered in PR#391 see https://github.com/Gnucash/gnucash/pull/391/commits/0171e0df079ebe9c5f2be183a475ea3d802af07f
Which is merged and will be released in GnuCash 3.5.