Smartphone: Installing lineageOS + Googles Play Store (and getting 9GB system space freed up)

After installing TWRP as bootloader i was wondering, how much effort is is to install an alternative to android on my old smartphone.

Heimdall & ADB were in place (see TWRP posting) - so let's start!

I downloaded the appropriate image from https://lineageos.org/ and i did the following on my smartphone:

Click on "Wipe"

 Click on "Format Data"

 Type "Yes"

 Wait

 Step two times back and click "advanced wipe"

Choose "Cache" and "System" and swipe to the left

Step back to home screen and choose "Advanced"

 Choose ADB sideload & Swipe to the left

and then type:

sudo ./adb sideload ~/Downloads/lineage-16.0-20200325-nightly-a3xelte-signed.zip 

[sudo] password for schroff: 

Total xfer: 1.02x                                                                                  

and then REBOOT...
(if you want a clean lineage OS)

If you want the google play store, then go to https://opengapps.org/

Download the appropriate package (i chose "pico" - https://github.com/opengapps/opengapps/wiki/Package-Comparison)

Then repeat the steps on TWRP (smartphone) for sideloading and type

sudo ./adb sideload ~/Downloads/open_gapps-arm-9.0-pico-20200403.zip

Total xfer: 1.43x                      

And after that the smartphone starts up with lineage OS and play store (To avoid problems: do not connect to mobile networks neither wifi within the startup wizard - this can result in a black screen and the wizard will never end).
The best thing: with Samsungs stock Android about 13GB was blocked by the system. Now only 4GB from 16GB are used. So i got additional 9GB free space. Really cool!