How do I insert an action using Context after Mono<Void>?

Question

        Mono<Integer> just = Mono.just(1);
        Mono<Void> empty = Mono.just(1).flatMap(integer -> {
            System.out.println(integer);
            return Mono.empty();
        });

        Mono<Context> contextMono = Mono.subscriberContext().doOnSuccess(context -> {
            String aaa = context.get(String.class);
            System.out.println(aaa);
        });

        just.flatMap(integer -> Mono.subscriberContext().map(context -> {
                String aaa = context.get(String.class);
                System.out.println(aaa);
                return integer;
            })
        ).subscriberContext(context -> context.put(String.class, "aaa")).subscribe();
        
        //No Execute
        empty.flatMap(unused -> contextMono).subscriberContext(context -> context.put(String.class, "aaa")).subscribe();

        //Context is empty
        empty.doOnSuccess(unused -> contextMono.block()).subscriberContext(context -> context.put(String.class, "aaa")).subscribe();

        //Execute multiple times
        empty.then(contextMono).then(empty).subscribe();

How do I add an operation after a mono that uses the data in the context and eventually returns the data from the original mono. It's all well good to use flatmap when mono has a return value, but when monoVoid, I don't know how to do it. How to perform operations that are compatible with elements and Void？