One Product Page, Five Use Cases: Picking the Primary Keyword

Some product pages serve several uses at once. We're working on a natural latex cushions page that covers sofas, chairs, office seating, benches and custom furniture. Which keyword should it lead with?
The trap. The current title lists three uses: "Cushion for Chair, Sofa & Seat". That reads well, but it splits relevance across three queries and leads with none.
How we're choosing:
Pull search volume and difficulty for each use ("cushion for sofa", "chair cushion", "seat cushion").
Check what already ranks for each: product pages, or category and marketplace listings?
Pick the term where a single manufacturer's product page can realistically compete, and lead the H1 and title with it.
Keep the other uses in subheadings and body copy so the page still matches them.
If one secondary use earns real traffic, give it its own page later rather than diluting this one.
Takeaway. A page that tries to rank first for everything usually ranks first for nothing. Lead with one term, support the rest. How do you handle multi-use product pages?