You could create a list of commands in a text file, and then pipe that into fzf. With a light wrapper that would allow you to type a portion of the command to select and execute it.
The Azeron and reWASD software are Windows only, unfortunately. That said, there is storage for two profiles in the device, so it can be used with a Linux machine after it is configured with the Azeron software. I've heard of folks using AntiMicroX on Linux to configure it, but have never tried myself.
If you're OK with stepping away from a standard keyboard, I have an Azeron Cyborg that I use for most of my games. Paired with reWASD, it is infinitely customizable. It's a bit pricey, but I love having a thumbstick in the mix. Not quite what you're looking for, but maybe it provides some inspiration?
I use Chrome Remote Desktop daily. I don't know if it's the best, but it works great for me. https://remotedesktop.google.com/
ChromeOS Flex is an interesting choice for kiosks. There's a great case study from Nordic Choice Hotels: https://cloud.google.com/blog/products/chrome-enterprise/nordic-choice-hotels-bounces-back-ransomware-attack-chromeos-flex.
AsciiDoc for plain text markup. It handles more use cases, and has fewer ambiguities in the standard than Markdown.
It hasn't been updated in 10 years, but still my go-to: https://play.google.com/store/apps/details?id=net.cactii.mathdoku
The process for submitting feature requests is here: https://source.android.com/docs/setup/contribute/report-bugs