For better astrophotography experience, here are some stratergies I usually if I were to shoot with a cell phone cam.
It starts with your smartphone itself, Your smartphone should be able to shoot at least 1080p and should offer manual settings. Make sure that you shoot images at JPEG (Check your compression rate, it should be in minimum, PNG format is always preferable) or PNG format and not in any compressed formats such as HEIC. Use voice control or a earphone to capture pictures so that you don't shake you smartphone
Planets or Galaxies, your exposure time should range between 30 seconds to 60
seconds, most smartphones offer this settings, longer the exposure time, more
details you see in the image
Capture images at no more than ISO 400 (ISO simply refers to the sensitivity to
the light, since high ISO in low light will produce disastrous noise in the
image), different sensors / smartphones offer different ISO range, anything from
25 to 400 will fetch you good images
For stacking you may need to take as much as 30 pics (Best results if you shoot as a video, not sure if some smartphones allows you to take videos with advanced settings/manual mode), since more images = more information to the software to fetch you good results in destroying the noise. Registax is my personal choice to stack images.
After stacking images, you can use Adobe lightroom for smartphone or Dark Table for PC which gives you the features that are enough to correct colors, contrast, white balance etc.