I'm late by a few chapters but I just suddenly thought of; what if she was reborn to check up on her orphan grandson? I assume that he's an orphan with no parents because she took care of him from small to a teenager. She still needs to check up on him, as he had barely turned into an adult. I hope she remembers & go on a journey to find him, if her rebirth time aligns with her death i.e. in the same flow of timeline.
@orochijes I have them in my country, but not at all places although it was popular in newer generation shopping complexes (2015 & above in my country I think) that promote green energy consumption.