Samsung shipped 2 new major Android versions, 7 and 8.0 to the device. This seems to be the end, so in early 2019 I started to use LineageOS on the Galaxy S7.
https://wiki.lineageos.org/devices/herolte/install worked for me, with one difference: after flashing the recovery image with 'heimdall flash –RECOVERY ..', the doc asks to reboot into recovery with “Volume Up + Home + Power”. At that point, I can just switch off the device with “Volume Down + Home + Power”. After turning it on again (pressing “Power”), and then immediately pressing “Volume Up + Home + Power”, I was able to proceed.
I planned to go without any spying, but my dependency on google maps is stronger, so I installed gapps.