You can save all that effort and instead come up with a CSS framework that enforces monospaced fonts, uniform font sizes, encourage information-dense layouts, have borders that don’t take up a cell (border: solid 0.1rem black; padding: 0.5rem;). Pair it up with a small JavaScript framework that listens to keypresses and buffers them. Furthermore, the framework makes the user decide on fonts, whether to allow images, whether to adhere to a strict character grid etc.