The outline a screen reader hears
A sighted reader skims a page by its visual weight: size, boldness, spacing. A screen-reader user skims the same page by pulling up a list of its headings and jumping between them. If that list is wrong, thin, or missing, skimming is not available to them at all — they are reading start to end, every time.
The list only exists if the headings are real
Bold text at the top of a paragraph looks like a heading to anyone looking at the page. It does not appear in a screen reader's heading list, because nothing marked it as one — it is a paragraph with emphasis, and the reader has no way to tell the two apart short of reading every paragraph looking for one that sounds like a title.
The fix is one menu, not a rewrite: select the line and apply a real heading level from the text-style menu instead of bolding it. The same problem shows up with hand-typed lists — a run of lines each starting with a dash or a number, rather than a real bulleted or numbered list. Read aloud, it is a sequence of ordinary sentences; a real list tells the listener how many items there are and when the list ends.
Skipping a level looks like a missing section
Heading levels describe nesting, not size. An H2 section holds H3 subsections underneath it; jumping from an H2 straight to an H4 does not read as a stylistic choice to someone navigating by level — it reads as though a subsection went missing, because from where they are standing, one did.
This is usually not a decision anyone made. It is what happens when a page is assembled from pasted sections written at different times, each with its own idea of where it sits in the document.
The H1 you already have
Confluence renders the page title as the page's only H1 before your content even starts. An H1 placed inside the body does not add emphasis; it gives the page two competing titles, and a screen reader has no principled way to decide which one is the real one. Body headings start at H2.
A heading is a label, not a paragraph
A heading that runs to two sentences works visually — it is still bold, still bigger — but it fails the one job a heading has, which is to be short enough to recognise at a glance in a list of thirty others. If the heading needs a sentence to make its point, write the sentence underneath it and leave the heading as the label.
Checking a page you did not just write
None of the above requires reading the whole page. Open the heading list a screen reader would build — most word processors and the Confluence editor both expose one — and read only that. A good outline reads as a sentence on its own: an ordered set of labels that describes what the page covers before a single paragraph is read. If it does not, the page's structure is the thing to fix, not any one paragraph in it.