I’d choose a single AA headtorch.

Usually powered by a lithium primary (Energiser) which are so lightweight, but alkalines also work.

I use one made by Mammut.

Otherwise something like an Olight S15, with a diffuser cone for use in the tent. I also have this.

Or a Nitecore MT22A (got that too).

Also add a backup, a coin-cell torch to clip onto a zip. With a spare cell or two.

Everything should be powered by primary cells, backpacking is not a situation to be bothering with trying to charge up secondary lithiums, even with dinky solar panels/powerbanks or, worse, thoughts of carrying chargers to use in hotel rooms etc.

Work out your likely usage and pack in enough cells to keep you going. Or plan on picking them up from wherever, when you pass civilisation. AA is the best format.

If you are in the military, CR123 is the other option, issued from stores.

Nobody needs a gazillion lumens of perfect CRI light, real word stuff can be so much more modest.