When you're in the FITS viewer and use a mouse scroll wheel to zoom-in, if you're not careful and scroll it too much, which is easy to do with Apple's POS scroll mouse it will ultimately lead to a crash. It zooms too far and appears to causes a memory leak as I've seen memory usage spike.
I've accidentally flicked the mouse on that screen, it would zoom way in or out then Kstars became unresponsive at first followed by a crash some time later. The solution is to not use that mouse and it works fine with another one. The mouse seems overly sensitive and possibly the software needs to ensure it doesn't accept input past a certain point.
Perhaps my experience on the Raspberry Pi 4B 8GB will be of some use to others. FIrst, I had wanted to use a passively cooled case (aluminum) without a fan to conserve battery power in at remote locations that could also be mounted to my dovetail bar. That worked fine. Then I wanted to use USB 3.0 thumb drives and SSD. Bad combination. The metal case weakened the signal, then the USB 3.0 port completely jammed whatever signal was left. I got it to work using a USB Wifi Adapter (Panda PAU06 or PAUO9) in the 5GHz band, but the range was still limited to less than 50 feet through one exterior wall, and was somewhat unreliable. You may need to disable the Raspberry's on-board wifi, or at least use the network configuration tool to specify which adapter should be used. I was able to run the wifi adapter from either the USB 2.0 ports on the Raspberry Pi, or from a powered USB hub. It seemed to work better plugged directly into the Pi, perhaps because there was less 2.4GHz interference on the USB 2.0 ports. Now I'm thinking to ditch the aluminum case in favor of plastic one with a fan so that I can get better wifi performance.
I have pretty decent Wifi performance with the internal Wifi AND with an external Wifi adapter SIMULTANEOUSLY. The external adapter is connected to my Wifi router, the internal Wifi creates an independent hotspot and all peripherals including SSD are plugged into a powered USB3 hub and that is the only cable that is running to the Pi. Everything is routed through the hub.
I 3D-printed a case for which I found an STL file on Thingiverse and which I modified so that I could fit it with a larger fan-operated internal heat sink.