The one terse sentence we got from the OP points more toward controlling an I²C based device from a Windows computer than manipulating internal I²C devices.

That's what a FT232H based board could do.

Also, a coworker got a recommendation to use https://spidriver.com/ to test third party SPI hardware by the maker of that hardware. It is open source hardware and software, with a repo at https://github.com/jamesbowman/spidriver. That device has two "sister devices" that speaks I²C instead of SPI: https://i2cdriver.com/, https://i2cdriver.com/mini.html, repo at https://github.com/jamesbowman/i2cdriver. There are no Perl modules yet, but if C and python can talk to the driver hardware via a simple (USB virtual) serial port, Perl should be able to do so, too. At least the serial port part is already done in Device::SerialPort and Win32::SerialPort, so all that's left to do is to stuff the right bytes into the serial port and pull out some other bytes.

Alexander