I don't think you'd want that website. Whisper is fairly efficient (even an old GTX can do pretty well at 4x-8x real-time speed), but a website like that would still require pretty expensive cloud GPUs. It's really not possible to imagine that a website like that would not be data mining you and selling all your audio to advertisers to pay off investors.

Better to buy a GPU and do it yourself. (Good news: it takes like 30 seconds to install)

For iOS and MacOS there is Hello Transcribe, a privacy respecting app which uses Whisper

Just use buzz.

Google Colab can run Whisper, but it can most likely also run on an old, cheap laptop that you have.

I used this yesterday: https://replicate.com/daanelson/whisperx

I used an hour long audio clip and it worked without issues. Though I don't know if this will be free forever.