Decided to make a little script that listens to textareas in post & comments, and if you press Ctrl Enter while focusing on them, it submits them. I use this to post comments faster and with less bother. It's reminiscent of the RES feature to do the same thing.

If you use Greasemonkey or Tampermonkey, you can install this easily and instantly have CtrlEnter to submit. Let me know any improvements I can make.

// ==UserScript==
// @name         Lemmy Form Submit with Ctrl+Enter
// @version      1.0
// @description  Submit forms with Ctrl+Enter in Lemmy instances so you don't have to click the button every time you want to post something.
// @author       God (https://sh.itjust.works/u/god)
// @match        https://*/post/*
// @match        https://*/comment/*
// @icon         https://join-lemmy.org/static/assets/icons/favicon.svg
// ==/UserScript==

var isLemmy =
  document.head.querySelector("[name~=Description][content]").content ===
  "Lemmy";

if (isLemmy) {
  // Define a global variable to keep track of the currently focused textarea.
  var currentFocusedTextarea = null;

  // Function to attach focus and blur event handlers to all textareas.
  function attachEventHandlers() {
    document.querySelectorAll("textarea").forEach((textarea) => {
      if (!textarea.dataset.ctrlEnterHandled) {
        textarea.dataset.ctrlEnterHandled = true;

        // Check if this textarea is currently focused
        const wasFocused = document.activeElement === textarea;

        textarea.addEventListener("focus", function () {
          currentFocusedTextarea = this;
        });

        textarea.addEventListener("blur", function () {
          currentFocusedTextarea = null;
        });

        // If this textarea was focused, blur and re-focus it to ensure event handlers get triggered
        if (wasFocused) {
          textarea.blur();
          textarea.focus();
        }
      }
    });
  }

  // Attach a keydown event handler to the entire document.
  document.addEventListener("keydown", function (event) {
    // If Ctrl + Enter is pressed
    if (event.ctrlKey && event.key === "Enter") {
      // If a textarea is focused and contains text
      if (
        currentFocusedTextarea &&
        currentFocusedTextarea.value.trim() !== ""
      ) {
        // Your submit logic here
        handleSubmit(currentFocusedTextarea);
      }
    }
  });

  function handleSubmit(textarea) {
    // find the closest type="submit" button and press it.
    textarea.closest("form").querySelector('[type="submit"]').click();
  }

  // Call the function initially to cover textareas that exist when the page is first loaded.
  attachEventHandlers();

  // Observe the document for changes and reattach event handlers when new textareas are added.
  const observer = new MutationObserver(function (mutations) {
    mutations.forEach((mutation) => {
      if (mutation.type === "childList") {
        attachEventHandlers();
      }
    });
  });

  observer.observe(document.body, { childList: true, subtree: true });
}