Icons as in hearts, hunger, and armor points. The backgrounds are like the grey icons that show up when you're missing points.
Less obtrusive as in smaller. Not completely removed, because that can get confusing when you can't tell if you have 10 or 12 health left.
I also threw in a few tiny inconsistency fixes because I'm nice

Health backgrounds are now small grey hearts.
Hunger is a bone with some meat stuck on it.
Armor backgrounds have been removed, because you're not really missing points.

Haha good luck seeing the heart backgrounds in the gallery because I was standing on bedrock while doing this
I didn't showcase absorption hearts because you can probably already imagine yellow hearts.

If I missed anything, or you'd like me to add more, feel free to comment below.
Frozen hearts will be added once 1.17 fully comes out