I'm using a 6 year old i3 laptop running win10, Resolve works fine but rendering can take 30 minutes for ultra HD clips. I started building a desktop but due to the graphics card shortage it's on hold.
There are many 12v charges that use a buck-boost circuit to charge batteries of higher voltage than the source. I have adapted my HP laptop charger that uses 12v from a cigarette lighter and outputs 19.7v to charge my drone from a motorcycle.