Your Roku 3 (released 2013) uses a 12v, 1 amp power supply with a 5.5mm x 2.1mm connector.
Roku 4802 is the current Roku Ultra, not a Roku 4.
Roku Ultras since model 4660 (released 2027) have used a 12v, 1.5 amp power supply with a smaller 4.75mm x 1.7mm connector.
The chart I consulted only goes to Ultra 4800 (released 2020), but this page at Crutchfield indicates the 4802 also uses a 12v, 1.5 amp power supply. Odds are very good that it is the same power supply as the 4800 and still retains the smaller connector to prevent an underpowered power supply from an older unit from being used..
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