App Store broken

Welcome, Michael478, to Apple Support Communities!

MacOS 10.13.x, High Sierra, is no longer (fully) supported by Apple.

The sad state of the Mac App Store, as seen from that system, is a symptom of this diminished support.

Fortunately, your MacBook Air, 2017, is capable of being upgraded to newer versions of macOS.

You would never find a macOS upgrade via the Mac App Store’s update screen, anyway.

Instead, use How to get old versions of macOS - Apple Support.

Make sure you perform a complete Backup, before attempting an upgrade.

You will also want to check your applications for compatibility with whatever new macOS you wish to upgrade to!

I can’t remember whether Mojave supports 32-bit Apps, or not, but certainly Catalina and beyond do not support 32-bit Apps.

@ Halliday is very correct about the state of High Sierra Apple Store.

If going to UpGrade - be sure to open the Links in the download page only in Safari as other may not work. Also, do a Time Machine Backup Before attempting. Mojave Does support 32 bit Application / extensions and Drivers. Again as @ Halliday mentioned starting in Catalina and Above - Everything Must be 64 Bit or it will not work. There is No Workaround.