So I was looking on our GCam thread and found it the most confusing thread I've ever encountered on XDA.
Hence, I decided to look for other sources to find a suitable version of Gcam with some recommended settings for our device.
So I have downloaded the F1 theme from the Internet. But the file manager icon was displayed as messaging.
I have just corrected that icon and reuploaded it.
Here is a 6.1 version with Night Mode working. In night mode the view finder is not working though and selfie cam has green hue.
Still slowmo is not working.
I have found the APK on the Internet.
Just install as normal APK.
All the credits go to the respective developer.
Just an update about why I am not updating the OP with new versions.
As per my own experience these almost "daily" new versions are not stable enough.