Even though I'm dealing with a newer version of springboot I had exactly the same issue with a specific version of SpringBoot

• Spring boot 3.2.10 (with springdoc 2.6.0) was working, showing the swagger page
• Spring boot 3.4.2 (with springdoc 2.7.x or 2.8.x) wasn't showing the page

I was blaming the newer version of springboot, but there was probably something wrong with my maven cache. I delete all the org.spring* stuff and this fixed the issue. If this didn't work, I would also suggest cleaning all the IDE caches.