Another option would be rechargeable batteries with a solar battery charger. Though I can’t speak for how effective such chargers are (or if it would be conveniently sunny when you needed it.)
That's OK if you can physically swap batteries. And you're not wandering around.
When batteries die (notice I don't say "if") they do so when you really need them. NOW. there's no substitute for physically swapping a live battery for the dead one. If it's mission critical, I want removable batteries and spares.
BTDT.