Hi all, lately I've started developing mods that are server-side only, so I've already started working with packets, I thought it was a pretty simple thing (having already worked on it when developing plugins) (I know it's completely different at code level, but logical I think it's the same) but I ran into multiple problems, I'm developing a mod in 1.19.2 server side which for now has to send a simple message to individual clients by executing a command, like a sort of "hello world" debugging. I developed the command part and it works, but I really have no idea how to send a chatmessagepacket to the client, could someone help me?

Test.java -- Command Class (Working)

public class Test {
    public Test (CommandDispatcher<CommandSourceStack> dispatcher){
        dispatcher.register(Commands.literal("test").executes((command) -> {
            return 0;
        }));

    }

    private int prova(CommandSourceStack source) throws CommandSyntaxException{
        ServerPlayer player = source.getPlayer();
        BlockPos pos = player.blockPosition();
        //here must send a packet to the client
        return 1;
    }
}

PacketHandler.java

public class PacketHandler {
    private static SimpleChannel INSTANCE;

    private static int packetId = 0;
    public static void register(){
        SimpleChannel net = NetworkRegistry.ChannelBuilder
                .named(new ResourceLocation(Mceconomy.MODID, "main"))
                .networkProtocolVersion(() -> "1.0")
                .clientAcceptedVersions(s -> true)
                .serverAcceptedVersions(s -> true)
                .simpleChannel();
        INSTANCE = net;

        net.messageBuilder(MessagePacket.class, id(), NetworkDirection.PLAY_TO_SERVER)
                .encoder(MessagePacket::toBytes)
                .decoder(MessagePacket::new)
                .consumerMainThread(MessagePacket::handle)
                .add();
    }

    private static int id() {
        return packetId++;
    }

    public static <MSG> void sendToServer(MSG message) {
        INSTANCE.sendToServer(message);
    }
    public static <MSG> void sendToClient(MSG message, ServerPlayer player) {
        INSTANCE.send(PacketDistributor.PLAYER.with(() -> player), message);
    }

}

MessagePacket.java -- (StringTextComponent can't find it and I don't know why)

public class MessagePacket {
    public MessagePacket() {
    }

    public MessagePacket(FriendlyByteBuf buf) {
    }

    public void toBytes(FriendlyByteBuf buf) {
    }

    public boolean handle(Supplier<NetworkEvent.Context> supplier) {
        NetworkEvent.Context context = supplier.get();
        context.enqueueWork(() -> {
            //On the server
            ServerPlayer player = context.getSender();
            ServerLevel world = player.getLevel();
            player.sendSystemMessage(new StringTextComponent("Hello World!"));
        });
        return true;
    }

}

Any ideas?

Why do you need a custom packet for this when vanilla already has something? You can probably just look at the SayCommand to see how to do this.