i would look into using Box Navy switches for the power button. Contact Novel Keys maybe? Its the biggest click of any switch out there and has a really strong force to actuate. would make a perfect power switch imo.
there is also a huge market for mechanical keyboard artisans to be used as power switches here
Kailh BOX Switches
Kailh BOX Switches. BOX switches are IP56 waterproof/dustproof. Only SMD compatible. Not compatible with other LEDS.
novelkeys.xyz
there is also a huge market for mechanical keyboard artisans to be used as power switches here