There were some subtractions for a bunch of stuff that wasn't getting much love to begin with. They removed their JS interpreter which was based on rhino which continued being a side library the entire time that java added it to the Java runtime. The only personal break that had no remediation was a minor helper class in JMX that affected me. Pretty much anything that was removed has some library addition that can add back what was cut. Basically Java 6-8 added a bunch of library support things that were probably better maintained as a third party library to begin with. The module system usually means adding some security policy exclusions for popular libraries, but in general I get a very well performing JVM that feels like it optimizes the code significantly better than in previous generations.

As a Java developer you should really set up at least some basic monitoring and perform load testing from time to time.

And even in the unlikely event you don't see any improvement with recent versions of the runtime, something like Spring Boot 3 requiring Java 17+ isn't exactly "invisible" in the Java world.