Mild tangent: are there smart glasses out there without camera, without needing internet access, and with custom app support? All my neck and back want is a way for me to look up instead of down whenever I'm bored and smart glasses would be one possible solution for that.
You can look for smart glasses (hey cyan) in aliexpress, and use claude/codex to reverse engineer. There's a guy who put an sdk on github. All you need is bluetooth to your phone, and of you go. You can build an app that does whatever you want within the firmware limitations of the glasses.