In past few weeks I have been developing Better Upload, a library that makes file uploads very simple for React. It uploads directly to your bucket in any S3-compatible service, like AWS S3 and Cloudflare R2. Multipart uploads work out of the box! Fully open-source.
It also comes with copy-and-paste shadcn/ui components. If you want more control, there are also hooks available for the client.
You can run code in your server before uploading, so adding auth and rate limiting is very easy. Files do not consume bandwidth of your server, it uses pre-signed URLs.
It is compatible with any framework that uses standard Request / Response objects, like Next.js and Remix. You can even use a separate backend server, like Hono.