An address even grandma can use without a cellphone

I am sorry but I see teams even going into cities with street grid patterns and affixing Plus Codes (with no QR code either) to smiling peoples houses.

What people really should be doing is assisting local governments to implement very strict real addressing systems, e.g.,
https://www.jidanni.org/geo/house_numbering/grids/algorithms/single_axis/single_axis.html

No longer do you walk away leaving them with only an address that requires a cellphone to navigate to.

Instead you also name their streets, in an integrated way that messes with the house numbers.

Even if there is no grid, Taiwan's nested alley numbering hierarchy can handle that.