To be clear, CR123A is not RCR123A nor 16340, i.e. primary is not secondary. CR123A is an essential option, but it is primary and running them has cost. Primary in single cell set-ups is pretty safe so long as you use decent batteries with a respected label. Li-ion secondaries require a little education -- to understand the risks and hopefully adopt best practices to mitigate risks.
If you want to entirely eliminate all risk regardless of circumstances, chose your light from those designed around NiMH. In my experience alone, my favorite LED drivers/LED combos seem to all be in AAA lights. But AA isn't much bigger, and it's less expensive with 3x the runtime.
IMO, AA Eneloop is the most compelling size and chem and label to run, but it is not easy (though it should be) to find a compact forward tailclicky or twisty-tail push button momentary single AA LED flashlight with modes (starting in low) that does not employ PWM or a similar scheme with pulses or whathaveyou (IOW uncompromising regulated Constant Current circuit, regulated CC in all modes), that has a high CRI emitter... these are just my requirements, but you should trust me, they should be your requirements also (sry, terrible argument! LOL).
Just be aware, speaking of most lights everywhere, some unfortunate decisions were made about design that seem to be ubiquitous across the industry for no great reasons, and though the industry is high tech and nimble enough to change, these unfortunate design choices seem to persist from one generation to the next across manufacturers while customers scream without much effect into the giant deaf ears of the flashlight industry. Many claim they have found the "perfect" light, but I think without the modding and custom flashlight community supported here and elsewhere, it would be impossible. The best flashlight is what the customer wants, and that's likely the only way to achieve full satisfaction without compromise.