I ran a very small mining operation at home back in the day and it definitely was all about trying to optimize everything.
Today, I don't think mining is economically viable without running a data center, but I still mine in the winter and turn my computer into a space heater for my home office. It definitely doesn't cover the power cost but it does offset a small portion of it.
Not affiliated in any way but Nicehash is what I use now since it (mostly) runs out of the box with minimal configuration.
As a side note, don't mine on laptops - you won't get enough heat to keep a room warm and you might end up with something failing from overheating.
That makes sense. CPUs and GPUs convert most of their energy use into heat. May as well do something slightly useful with that.
No idea what the numbers are now, but last winter, I think my 3080Ti cost ~$2/day to run and generated ~$1/day in crypto.