Hi @Matthieu,
The answer to your question would require some experimentation with the model in the various scenarios, but it’s generally cheaper to use CPUs and scale horizontally so you can achieve high throughput. You can find a some nice case studies here:

How We Scaled Bert To Serve 1+ Billion Daily Requests on CPUs - Roblox Blog 20
[2010.13382] FastFormers: Highly Efficient Transformer Models for Natural Language Understanding 8

Regarding frameworks, I usually deploy my models with FastAPI + Docker and have not found a strong need to use torchserve yet (which is experimental in any case). For clouds I don’t have a strong opinion, but have generally found the UX of GCP to be better than AWS  Other alternatives include Azure or Paperspace Gradient, but I’d definitely do some investigation before committing to any of the providers
HTH!