How do I write vim-latex like custom key bindings into the Overleaf (Codemirror) editor? - vim

Question

I am aware that Tampermonkey (https://www.tampermonkey.net/) could potentially do this. I installed a Tampermonkey chrome extension, and under "Dashboard", I added the following userscript (All the commented-out lines I tried below << CodeMirrorVim.Vim.map("jj", "", "insert");>> didn't work).
// ==UserScript==
// #name Overleaf Editor Custom VIM Keybindings
// #namespace http://tampermonkey.net/
// #version 0.1
// #match https://www.overleaf.com/project/*
// #grant none
// ==/UserScript==
(function() {
'use strict';
window.addEventListener("UNSTABLE_editor:extensions", (event) => {
const { CodeMirror, CodeMirrorVim, extensions } = event.detail;
// add custom keybindings - insert mode applies on insert
CodeMirrorVim.Vim.map("jj", "<Esc>", "insert");
// CodeMirrorVim.Vim.map("kk", "Right-Right", "insert");
// CodeMirrorVim.Vim.map("ECI", "\\cite{<++>}<++>", "insert");
// CodeMirrorVim.Vim.map("aa", "<Down>", "insert");
// CodeMirrorVim.Vim.imap("`a", "\alpha", "insert");
// CodeMirrorVim.IMAP('FMB', "\\mathbb{<++>}<++>", 'insert')
// normal mode applies while escaped
// CodeMirrorVim.Vim.map("h", "j", "normal");
// CodeMirrorVim.Vim.map("hh", "<Right>", "normal");
});
})();
CodeMirrorVim.Vim.map("jj", "<Esc>", "insert");
works but
CodeMirrorVim.Vim.map("kk", "<Right>", "insert");
CodeMirrorVim.Vim.map("kk", "Right-Right", "insert");
CodeMirrorVim.Vim.map("kk", "<Esc>-<Right>", "insert");
all didn't work. So how do I write, for example, the following bindings in 'tex.vim" in Tampermonkey userscript?
Here is keybindings in my "tex.vim":
call IMAP ('FTX', "\\text{<++>}<++>", 'tex')
call IMAP ('FCA', "\\mathcal{<++>}<++>", 'tex')
call IMAP ('EBM', "\\begin{bmatrix}\<CR><++>\<CR>\\end{bmatrix}", 'tex')
imap kk <C-j>
Also it would be nice if we could input greeks in overleaf CodeMirror editor as we do using vim-latex:
typing "`a" gives "\alpha".