How can I change T to Flux<T> for a controller's method's return type?

I have a method looks like this.

@GetMapping
Some read() {
    return getSome();
}

Now I want to change the result's type as a Mono as leave the getSome() non-reactive.

The question is which one is better? Or are they equivalent in the context of reactive system?

@GetMapping
Mono<Some> read() {
    return Mono.justOrEmpty(getSome()); // getSome() is still non-reactive
}

@GetMapping
Mono<Some> read() {
    return Mono.fromSupplier(() -> getSome()); // getSome() is still non-reactive
}