How to fully back up a phone's content to a PC, possibly for restoring on a similar phone
LG provides different Software (or maybe just different names)
- LG-Bridge
- LG PC Suite
- LG Mobile Switch
- LG ANDROID BACKUP  

For experts also there is LGUP flash tool which may shipped with qualcomm factory loader, with this you may able to create/restore full partition dump, root the device without data loss, or install TWRP via EDL mode