When a driver is designed the input voltages are taken in to account for every single component on the driver such as ic’s and capacitors. Resistors have to be power rated.
If you double the input voltage theoretically, you would need twice the power rating of a resistor for it to work properly, depends on the design.
Most of the time components are selected above what the actual rating needs to be. A little overhead is built in to ensure proper operation under varrying conditions because sometimes ratings are inflated from manufactures.
A driver that’s designed to work with a input voltage of 4.2v max can probably with stand a input voltage or 4.5v or so but when you push the voltage even higher, the magic smoke will soon follow. Some drivers are being run right on the edge of destruction in the first place, so adding more voltage may cause failure pretty quick.
You’ll need to find a driver that’s made for your input voltage.
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I thought this driver used by Mrsdnf was pretty interesting.
The seller has a few on ebay that might work for you. They seem to have a few different settable options.