Any particular reason why you are setting up kstars/ekos on the RPi?
You could just install INDI and use your windows machine to remotely access it via kstars/ekos... makes for a lower resource intensive solution (i.e. you could use the Rpi2).
<Late Edit>
What's USB output amperage on the battery? You'll have to make sure it's 3A if you want to power the RPi4 and use the USB ports at maximum capability
http://www.astrofriend.eu/astronomy/...pberrypi4.html
</Late Edit>