If you need to expand your Mac storage in a big way without breaking the bank, your best bet is with external hard drives.
Even if you have a single computer at home, you can start your own server and run all kinds of services, all thanks to Proxmox. Here's how I did it.
Underneath ChromeOS, many older Chromebooks are still perfectly functional, low-power computers with solid CPUs, built-in batteries, decent storage, and all the peripherals you need to get started.