I can't navigate the Eclipse UI - i'm too unfamiliar with it.
There seems to be a workable solution here, though.
If your version of Eclipse doesn't have the Java-> dropdown, then there's another way to get to that tab;
Properties -> Java Compiler; uncheck "Use compliance from execution environment" and change the compliance level to something really high, like Java 14. It will complain that you don't have a Java compiler capable of making bytecode that high level, and will redirect to the "Installed JREs" tab.
Annoyingly, Eclipse calls the JDKs JREs, and it should not, for they are different, and should not be confused.