If you are looking for a hardware-level solution that bypasses Windows OS limitations entirely: USB to USB Converters : Using a "Hassu" converter with TMK/QMK firmware can turn any standard USB keyboard into a fully programmable macro board
: A popular DIY approach where LuaMacros identifies the keyboard ID and passes it to AutoHotkey for script execution. multi keyboard macros crack
can identify specific hardware IDs for each keyboard. A popular Instructables guide details how to use a If you are looking for a hardware-level solution
Streamer: Full keyboard + Stream Deck + number pad such as email signatures
: Automates the typing of repetitive text blocks, such as email signatures, greetings, or hashtags.
A sample script looks like this: