Hi, I have a few suggestions. Here is my reasoning behind them:

While I do enjoy the option to hide certain aspects of hud fully (health, food bar), I consider the hotbar too important to fully hide. Reason being is that I don't always remember at what position the item I am holding is, which I found problematic especially when fighting mobs (with other HUD parts I don't have similar kind of a problem because I just set them to show when not full). I know about the events like attacking that triggers the hotbar to show, but I was looking for a way to show the hotbar even before that. I figured out two ways, but they do not exclude each other and I find both of them quality of life improvements. And even though I am talking specifically about a hotbar, those suggestions are also applicable to other components.

1. Opacity (transparency) slider

Probably the simpler solution would be to introduce an opacity slider and instead of making the bar disappear fully, it would become transparent after a certain amount of time (as well as the items in the hotbar). On an event that would normally pop the bar up back to the screen, the bar would become fully opaque.

2. An event to check a biome or a mob radius

Another approach would be to make the components show up in certain biomes like caves. A better way in my opinion would be to introduce a "combat mode" that would force the hud to show up, similarly how elden ring and other games do it. That could be achieved either by detecting if a hostile mob is located in a predefined (circular or square) radius or if the player has been targeted by a hostile mob (not sure about the right terminology here, but what I mean is that the mob has noticed the player and transitioned to an aggressive state from a passive state). The smoothest experience would probably be achieved by combining both the radius and the player being targeted approach, but that I believe would be quite complex.

Anyway, thanks for the awesome mod.

Hi, thanks for the feedback!

Your request 1 is already implemented: under "Advanced", you can set a "fade-out limit" (either globally or per component); and for the hotbar in particular, "Components / Hotbar" has a "Fade-out limit for items" setting. If you set these to, say, 0.3, then they will always render with at least 30% opacity.

As for request 2, I have wanted to implement a combat mode since I started this mod. It is surprisingly difficult for a client-side mod to figure out when the player is in combat. It is somewhere deep on my todo list, though.
I do like the idea of checking for cave biomes.. that could be very nice and is not something I thought of before. Maybe even a "reveal UI during night" or "reveal UI in non-overworld dimensions" could be interesting settings.