The main key metric for server load for something like Lemmy is CCU (concurrent users). That’s unfortunately not provided, but a good rule of thumb is that it’s going to be around 1-2% of DAU. That’s not provided either but MAU is, and DAU is typically going to be 10-50% of MAU. So with a MAU of 2700, we’d expect a DAU of around 600, and a CCU of at most 12 or so users. That’s easily achievable with a single 10€ VPS, though it definitely doesn’t have much headroom.

You could easily serve that workload on a t2.micro instance which is around $10/mo - a far cry from the $27,000 quoted in the image.