I tried out 2Keys

[codemicro]

It works. Setup is a little tricky, and involves static IP addresses and SSH. I had a few issues with the install process, but a few issues on the Github repo and quick support from Gum-Joe meant I had it up and running in no time.

Writing and updating macros is easy. When executing macros there is a small (but noticable) delay. It's nothing major, but it's there.

When it's up and running, it works great and has no issues. If you already have a Raspberry Pi kicking around, it's worth giving it a shot before buying anything else.

For the spreadsheet:

Thing	Other thing
F13 - F24?	Yes
Distinguishes between keyboards	Yes
Per-key RGB?	No
Screens for each key?	Unknown
MIDI support	Unknown
Language and international keys	Unknown
Supports all scan codes	Unknown
Direct launch for .exe and .bat files	Yes
Media keys remappable	Unknown
FN key remappable	Unknown
Little to no bugs	Yes
Do I like it?	Yea
Notes	Slight latency on keypress
Dollar per macro	$0.34 per macro, based off a 2GB RPi4 and 101 key standard US keyboard

[Gum-Joe]

Some notes from the author himself:

1. First, thanks for opening this! It's greatly appreciated!
2. The keyboard scan codes that are supported are taken straight out of the Linux UAPI file. See this comment in detector/twokeys/util/keyboard_map.py:

"""
Keyboard mappings
Copy paste from https://github.com/torvalds/linux/blob/master/include/uapi/linux/input-event-codes.h:
/*
 * Keys and buttons
 *
 * Most of the keys/buttons are modeled after USB HUT 1.12
 * (see http://www.usb.org/developers/hidpage).
 * Abbreviations in the comments:
 * AC - Application Control
 * AL - Application Launch Button
 * SC - System Control
 */
As such some c code is leftover (mostly '#define's.)
None = invalid key
An array of key mapping means multiple keys can correspond to it
Currently 249 keys are mapped
"""

It is also worth noting you can add your own key codes to use in the config files, so in theory, all scan codes are supported (I think I tried testing this by commenting on of the keys out of the mapping file and then re-adding it as a custom key and it worked, but I personally haven't testing anything outside a standard UK layout keyboard).
3. Media keys are not supported, though this is because they are logged to a separate file (in Linux, everything is a file in effect, so to watch for keystrokes we just read from the right file). See Gum-Joe/2Keys#32
4. Latency could be solvable via Ethernet (I am using Wifi), but will probably persist as an issue
5. The plan is eventually to automate static IP address setup and installing the necessary dependencies by sshing into the Pi and running setup automatically. Though this is quite low down the feature list. (see Gum-Joe/2Keys#1)