I have the same feeling as epninety about UBports. It's a good OS, well finished, but I still prefer Sailfish and Silica (unfortunately it's closed source, but still it's flexible thanks to patches, gestures are more parcimonious than they are in Lomiri, and multitasking and events are more convenient).

I have had the same issue with GPS, and another user too. Keyboard backlight can be activated manually with a "echo 1 > /sys/class/leds/keyboard-backlight/brightness", but there is no MCE to automate it, and it will be off again after the phone is locked.

I am sorry to hear you've had issues flashing back to SailfishOS epninety. A general notice, everyone be careful with the guide if you are flashing to 3.4 because things changed significantly with LVM encryption, and I haven't done it yet, so it's very likely that things are now inaccurate in the guide. However, I heard there is now a "flash.sh" in the 3.4 SailfishOS image, so there shouldn't even be any need for TWRP to go back to SailfishOS, I assume everything is now done with fastboot. TWRP can still be useful for backups, but it may not be the only or even the simplest way to install Sailfish now.