My brother-in-law runs his own data center/GPU farm at home.
Currently makes him ~$3k/month profit. 30% solar powered. Aiming to get to 60% by end of this summer which will increase profits significantly (mostly down to adding batteries, not panels), then will buy more GPUs.
He sells the compute via some 3rd party service that takes a cut. Apparently a lot of ML/rendering workloads.
You can just do stuff!