No AA cell is "about 2 volts." Alkaline can be 1.65V when fresh out of the package, and L91 Energizers can be 1.85V when fresh. When doubling cells, the single LiFePO4 14500 is a close match, when well rested after charging (charges to 3.7V, but should rest around 3.4V). That LiCo Li-ion charges to 4.2V, which is really too high compared to 2xAA cell voltages. The chemistry is also not all that safe... that cell has the chem with which most problems occur, which is why protection circuits with that chem are desireable. Though your camera isn't expensive, relatively speaking, continuously providing it with voltage over specification will eventually ruin its circuits. Hard to believe your Eneloops are not giving you the desired results, but it is possible. Eneloops would not run my Apple Bluetooth keyboard very well either (but there is definitely something wonky with my kb).
A safer chemistry option than even LiFePO4 would be to use 1.6V NiZn rechargeable cells (fully charged, they are around 1.9V, though that drops off rapidly when resting, and continues dropping... there are no LSD NiZn cells, unfortunately). NiZn are fragile, don't tolerate overdischarge, and rarely will you get the advertised number of recharges out of them, but even with a lifecycle of 20 recharges (assuming overdischarge abuse), they are far more economical than Energizer L91 Lithium primaries.