You’re using Spring Framework 6, and since Spring 6, the minimum supported Java version is Java 17 (the class version 61 is the class version of Java 17).
As documented in the Spring Framework Overview for Spring 6:
As of Spring Framework 6.0, Spring requires Java 17+.
So, if you want to use Spring 6, you need to upgrade to Java 17. If you want to continue using Java 11, you need to downgrade to Spring 5.3.
Given Spring Boot 3 is built on Spring Framework 6, the same applies to Spring Boot 3: you need to upgrade to Java 17, or you need to downgrade to Spring Boot 2.7.