A UTH will be just fine by itself as long as the cool side of your set up doesn't drop below 75° .... A heat lamp tends to make it a lot harder to keep proper humidity. You can use the UTH as your hot spot just keep it between 88 to 92°
As long as you can keep your cool side ambient temps between 78-82 and the hot spot on the glass inside the tank at 90 (it will be cooler on top of substrate) then your good. Try covering most of the top with aluminum foil to conserve humidity. I find it easier to keep the room at 78. A bit hot for us but once the reptile room is ready we can move them from our bedroom. Good luck
You NEED a thermostat with you UTH and an UTH does much of nothing for ambient temperatures.
More than likely you will need both unless you keep a very warm room.
I can tell you my home stays at 68F and I still have two glass tanks, a 10gal and a 40gal. The 10gal needs one light to heat it for my hoggy but the 40gal needs a 100w che, 60watt bulb, and a uth to keep it right.
If the room your cage is in does not stay warm(74+) and you are using a glass tank you will probably need a secondary heat source.
KMG
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