Save Files in Soft Brick and make it Boot again

I wanted to sign in to Snapchat but apparently, that doesn't work if you have root.
I then uninstalled the Xposed Framework and ignored it saying I should wipe dalvik cache (I now know that's stupid but I don't have a recovery or some option to do that rn)
Next, I went to SuperSu and did the full unroot.
After that I was told to reboot and now I'm stuck at the picture you always see before the bootanimation starts.

I'm looking for something like Titanium Back to get really everything saved and from there on make my phone boot again, stock rom is good enough.

I have access to a Windows PC which doesn't recognize my phone via USB, a big enough SD Card.
However, I don't have a custom recovery installed and when I try going to the stock recovery, it just says "No Command".
If I boot into fastboot, the phone acts as if everything was the way it should be while my PC still doesn't recognize it
Also, I can't remove the battery on this phone but making it go empty doesn't help either.

We´re talkting about my Umidigi Crystal 2/16 Version <-- The 2/16 is a different version!!
And it was running stock rom which was Android Nougat.

I´m not that experienced whith these things, you might have guessed it.
Thank you for any help though.