The Amiga 600 and 1200 only provide 5Volts max via the PCMCIA as I recall. Also this is the early days version of PCMCIA. What you describe will not work in an Amiga.
As for PC. Then you are best trying to source an older Laptop. You will be hard pressed to find anything like a PCI or even a PCI-E PCMCIA adapter. Even my 2010 Toshiba laptop only supports the latter PCMCIA-II standards. Good luck 🤞🏻
