tl;dr: Adding a challenge tracker would be good, the rest of the UI needs to be compacted down, or have varying degrees of compactness (normal, compact, minimal), and you're all very handsome/beautiful.
Obviously the more challenges you'd track the more screen revenue would be taken up, but there's ways around that: make the tracker collapsible in-game, any challenges completed during the game can be removed from the tracker, adding a tracking limit, etc.
Let's face it, the UI could use an expansion on, or at leasting varying levels of, the 'compact' option that we currently have (which really only effects the looting portion of it to my knowledge). There's a lot of useless fat that an experienced player has zero need for cluttering up their screen.
Again, threw together an example of what could be trimmed down:
That's obviously pretty rough and could definitely be more in-line with the Apex style, but I'm sure you can get a sense of what I'm trying to trim down: Player/team health and armor, loadout icons, option to remove the killfeed size of the consumable/throwable icons, etc.