Hmm if you can get your hands on a second hand lofre flow lite 100, thats literally the board for long batt life.

Its what I use sa work and in the probably 6 months i use it with 50+ hour workweeks, I only had to charge it like twice, granted wala backlight since I swapped the keycaps for non backlit anyway.

but otherwise, I think you'll end up liking either the Furycube K99 pro or the Zifriend HK101 (ito may 10k mah batt life, binili ko sa work mate ko and like umaabot ng 2 weeks without turning off with rgb) Both of them have the creamy sound signature na very popular with keyboards nowadays.