Svelte is an excellent framework! It's almost like writing plain HTML. (React, on the other hand, is cursed and a pain in the ass to write - I speak from personal experience.)

You can't go wrong with Ruby on Rails + Postgres + Bootstrap. If you've never done a website before, it's valuable to pick something standard so if you run into any problems you have the confidence to know that your issue is solvable.

and be able to edit the essay in all of those views

An old-school way to do this is with templates. But it can be awkward and hard to merge if somebody did write 3 different essays. A modern option is to use an LLM: Prompt it to "detect if two essays are the same essay but worded differently", or to "apply a semantic diff from one essay to another".

You may also want to write some simple scripts to output the reports/pages you want on the command line. "Given a folder of essays and a spreadsheet with all the other data, output some formatted output on the command line that I think would be useful". "Given a file that is a diff, a folder of essays, and a spreadsheet, output a new folder of essays with the diff applied".

It sounds like overkill or extra work to write such scripts first, but when you build your website you'll be able to say "I know approximately what the page should look like and how my data is structured. I just need to get the web framework to do it." You won't be mixing questions about what you want it to look like, with how to do it or how to represent things.

In any software project: Always start with the "most uncertain part" first. The frontend might be ugly(even a command line at first), but you know it can be improved. The data is used by everything and harder to change later, but you've already collected it in the form of spreadsheets it looks like. So I would say the API that defines all the operations is currently the most uncertain part. (I would start with an HTTP API and test with a script or a tool like Postman, but if you've never done that you can consider command line scripts). It sounds like the document editing is pretty standard, so you're asking if you can embed Google Docs; but if your project had a more sophisticated diff-aware multi-document editor that could edit 10 documents at once and also show them in real-time, I would actually say you should prototype the frontend first because that's a complicated UI. But if it's simple, you can trust that you'll find an editor later when you need it.

Then once everything is approximately defined, just read the Rails tutorial, set up a new project with Postgres and Bootstrap, and do everything you did before in website form.

You could make it a Google Docs+Sheets extension so there’s less barrier to entry + you don’t have to compete with their very good text editing and UI. Also AI integration could be useful—you put all of your ECs and awards and whatever in the spreadsheet, and ask an AI which ones are the most important for each college.

Also you mentioned that you are looking at the Common App API, and from what I’ve found on the internet, it seems quite limited and I don’t think you can import outside text into your applications. Additionally, I don’t think that everyone has access to the API, so you would probably have to be authorized by someone that works there.

If you are willing to do some manual curation, you could add each (commonly applied to) college’s questions as a “preset” every year so people don’t have to manually copy paste them off of each website.

You could look into Figma for designing it and helping with the layout and UX.

I took some SQL in college. It's used for databases a lot, but I found it really hard to learn. It would be a good tool for that if someone already knows it, but learning it for one project would be hard probably, although maybe you'd be better at it.