Welcome back! =)

The settings are a bit confusing, aye, but fear not - we can help.

So they are only UI scaling. The actual video resolution is a completely separate setting. You can resize most UI elements, but there are two problems with using only that setting when you use higher resolutions:

1. Elements can only be scaled up to a max of 140%. This is still too small at high resolutions for many elements.

2. Some elements (such as those nameplaces) cannot be resized in this fashion.

So to fix these issues, there's the UI settings you're looking at. It sounds like you want to actually use the "full HD" one rather than the 4K one if you feel the "GIGANTIC" nameplates are not to your liking. After that, you'll want to go through individual elements in HUD layout and do the scaling per preference between 60-140% of their original size.