WYSIWYG Editor For WordPress Fronted, complete Vanilla JS

Create a JS-based WYSIWYG Editor integrated into WordPress Website run a WordPress-based website that is a UGC (User Generated Content) platform. I want users to be able to format their blog posts before publishing. WordPress core and TinyMCE are too heavy and too expensive respectively. I want to implement the same functionality of TinyMCE 7 (free version) via custom code in my site. Requirements of the WYSIWYG Editor: - Support for bold, italics, underline, link insert, link remove, align, highlight, font size, font-family, tables, and more. - Support to format HTML tags automatically. Auto add/remove tags to make programmatic sense. Auto format text pasted from WordPress - Proper functions so that I can programmatically insert content in the editor. - Quickbar to show relevant tools, easily. Basic image manipulation like alignment and size. Preferably the toolbar is inline. - Support to have it as fullscreen with a click of button. - and anything else that free version of TinyMCE can implement - No libraries. Libraries make things heavy, and I would want a lightweight techstack. You can use jQuery, since WordPress already uses it, but any additional library would be a big no-no. - Functions: Lets make functions, hardcoding everything can be fast, but not scalable. This project is just beginning, we would need to customize and make changes, so making functions from your side would help us with the same. Make functions that we can directly plug into (like default content when loading the Editor, function to add buttons to toolbar). We are working on a massive project. Currently its our first time with Upwork, so this would be phase 1 of our 3 part plan. Once we are through with it and have good experience with the dev, we will be putting up another order in late May or early June. - Should have hashtags support, like in Twitter/Insta, if we type hashtag, it should automatically convert it into a link (I will take care of the backend) - Autocomplete links: Shouldn't be difficult, but using regex or whatever you like, when you see a text URL auto convert it into hyperlink - Block tags: Auto block and remove certain tags, like someone is trying to insert scripts, block 'em. Preferrably Inline editor like Gutenberg. The current setup of everything being at top is a bit old fashioned though completely functional. A block-based system with modern inline editor would be really great. - Shortcuts: It should support shortcuts. Obviously things like bold, italics, and underline should work (duh, it should be obvious). But, we also use CTRL+S in our current system to Save the form via AJAX. The saving functionality is built from our side, just that you should have functionality to pass such key presses our of the WYSIWYG IFrame. - Buttons: We have a lot of our functionality running over TinyMCE, this includes our own tools for monetization, inserting YouTube videos, etc. The code for that already exists from our side. We would just need the WYSIWYG to have functionality to add custom Buttons from our side (just like TinyMCE). We will handle the rest. - Height: Editor should automatically adapt to the height of content. Our average content in 1500 words long, so I cannot have an extremely long editor open by default, it should grow its size as the user types - One thing that has been an issue with most WYSIWYGs is that lets say you insert an image and a table, between them there is no gap to add another paragraph, which means mostly you have to edit Source Code to add another para. Not ideal, it should have a add para button for each "block" to insert para below/after every block - Noneditable: Like I mentioned we have some buttons to insert specific content. This content could include shortcodes, embeds, and various things that are plug and play, no need for user to edit. So, once added we want them to non-editable by user. They can backspace it to remove it, but can't as such change it. So, perhaps a CSS class that makes the div and all its children uneditable.