As others have said, no issues as long as there's no significant delays.

One tip however - after going through customs go in the direction for connecting flights (they will potentially try and send you the other way). Then once you go through the glass doors, turn left (they will normally try and send you right) which will get you to the United bag-drop area.

If KE tagged your bags all the way through (try and get them to - you'll need a copy of your UA itinerary when checking in with KE) you can drop them there. Otherwise keep following the signs to the UA domestic check-in area.

This'll get you to United check-in counters/security/etc quicker than the ways they normally direct you, which will either send you to International arrivals, or towards terminal 1/Intl A for SkyTeam connections.