The Pi Pico is actually used as the microcontroller for the BlueSCSI, which provides SCSI hard drive emulation and Wi-Fi support to actual still-running vintage Macs
https://jcs.org/2023/08/23/scsiwifi
The irony is that Gemini is probably not possible because it requires a modern TLS stack and the Macs are too slow to support the crypto themselves (though I've added TLS-offloading support to the BlueSCSI firmware to get around this).
I've written some modern software for these Macs if you're interested: https://jcs.org/system6c