What's the quickest way to build a low-code web app (SPA)?

Hi everyone! I'm going to start on a side-project this week, and hoping to go the low-code way.

For a full-fledged app I generally use ASP.NET Core or Node.js (with a web server and proper database), but for this project I'm trying to find the quickest way to build a low-code single-page web app.

I'm thinking of creating a simple website using Carrd, building the business logic as cloud functions (FaaS) on Azure or GCP, but I'm not sure how to go about handling data storage (mainly user accounts) and glue code (to call the cloud functions etc.). Maybe Cloudflare Workers (Sites and KV) will fit the job.

I'll appreciate any suggestions or tips! The main idea is to build something and iterate quickly.