Check out the Fenix BTR20. I prefer it to Fenix's new BC30. Greatly prefer it to the Magic shines, which are too bright and very white/blue light with zero attempt to shape the beam

Buy a spare set of 3400AH 18650 Panasonic batteries. One set runs more than 5 hours on medium-hi and 8 hours on medium. I never use hi, so, not sure....certainly more than 2 hours.

One set of batteries is more than enough power to do a 600K Brevet; so, I suspect it would be ok for commuting.

Or, if you have the funds you could overspend on a dynamo that could not blind a mouse, flickers when climbing, and loses light when stopped for a bit, weighs more, creates 6-8 watts of drag, and you could attach it to a light with connector reliability issues allowing water to infiltrate or worse there are some that have an actual opening at the bottom to let water spray or insects inside but the effect is the same.....they leave you stranded unless you carry a battery powered backup.

Tongue in cheek, supposedly newer dyno lights are not as problematic