The reason Jupiter moves so fast out of the field of view is not Jupiter's motion, but the Earth's motion.
We are whizzing around so fast that at high power you will struggle to keep the planet in the FOV for long, this is normal.
If your seeing conditions are good, then less power (higher numbered eyepiece) will keep it in view for longer and the image will be a little clearer, but you will probably not see as much detail.
One reason tracking and goto dobsonians are good value, they "hold" and track the object using sidereal (Earth rotation) motors to keep the sky synchronised to the movement of the Earth.
"Nudge, Nudge, Nudge" is the order of the day for any manual dobsonian user unfortunately.
Cheers
Chris
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