As there is no LTA/LTS anymore for the SonarQube Community Build (formerly SonarQube Community Edition) you are right, that the LTA version for SonarQube Server is 2025.1 and therefore the Sonar Plugin API version is 11.1.0.2693.
The API version is stable for the lifetime of the LTA as the Sonar Plugin API is developed alongside newer versions of the Sonar products and changes / fixes are only backported to the LTA - but no (breaking) changes to the Sonar Plugin API.