First change I would love is that the message for toggling features on and off would appear somewhere else on the screen. I am using VanillaTweaks' Coordinates Hud, and I can see the message for a brief split second before the coordinates hud takes over that position again. If it was possible to make it appear somewhere else and not being overwritten like this, it would be great.

Second suggestion is an icon somewhere along the edge of the screen, similar to the potion effects, to see if a feature that have always active effect but is not necessarily visible, like fake sneak, is enabled or disabled.

I recommend you mini hud instead of a data pack because you can use it on other servers since it is client side

But the problem here is that if the server has such a data pack, it will currently interfere with the client mod toggle messages.

I will probably by default move into using a separate similar hotbar message in malilib, so that the vanilla messages don't override it, and I will probably also add an option in malilib to decide where the normal toggle messages should go to. It will have a few different options, such as the custom hotbar message, the old vanilla hotbar message, and some different malilib message renderers or toast messages (that already exist and are used for other message types currently).