Recommend me a tech stack / SaaS boilerplate for a collaborative spreadsheet

I want to build a collaborative spreadsheet web app (think google sheets) with a focus on education. I need the following:

• collaborative features (realtime)
• user accounts
• a grid component, maybe ag-grid

I don't want to re-implement the wheel for the following:

• user accounts (creation, login, password change , etc)
• subscriptions / billing
• the marketing workflow (for following up on trial users)
• design. I'd like to just use a theme which gives me beautiful buttons out of the box.

So I was thinking Supabase, which will give me user accounts / realtime sync. For subscription and billing. I don't know yet which framework i'm using but learning towards Vue or Svelte which both seem to have support.

For marketing workflow, i'd like something like Convertkit which automatically keeps my user accounts in sync.

For design, everyone seems to repeat "Tailwind" so I was thinking of blindly following that recommendation.

Based on the above, does anyone have any recommendation ?