Many label printers (especially the older ones) use a proprietary text-based language, and accept plain vanilla text input via their serial port. They don’t use a printer driver as such. To use one of them you have to learn their command language (usually pretty simple) and write a text file describing what you want to print using that language, and upload the file to the printer.

Start with the printer documentation and go from there.

Newer printers need linux drivers. Support varies.

You’re thinking of adaptive lenses (that darken when in sunlight). OP has progressive lenses, which are a kind of bifocal lens without a sharp dividing line between the near and far vision parts.

You aren’t wrong though.