A CSV tool I needed for personal use

Hey guys,
This is not really a startup (even though I might launch a paid version in the future).
It's a tool I've been meaning to make for a long time and I finally put some time and made an MVP.
I often had to convert a CSV by picking, changing, or merging some columns of a CSV. Making the script with javascript is simple, but if the CSV has more than 40k rows, the processing would be pretty slow. So then I had to use Python which usually takes me longer to do as it's not the language I use daily.
CSV Fiddle makes it easy to transform a CSV being small or big using a simple javascript function that takes a CSV row and returns another.
You can write your code in the code editor and CSV fiddle will use web workers to parallelize the work.
An enormous file I tried had 200mb with 2M rows and it took CSV Fiddle with 200 threads 45 minutes to finish the transformation.

The main functionality runs in the browser so I will keep the browser version free forever. For later features like saving the config, I will use supabase which also provides a free database so I won't have any monthly cost for maintaining it.

I do have a plan to provide a cloud version for people who want to get faster results for bigger files or don't wanna keep their computer open for such a long period of time and it would be paid as you go basis so there are no monthly or yearly subscriptions.

Let me know your honest opinion (apart from the UI as I'm a backend/infra person with 0 FE talent :)) ).

Cheers