By "fast/efficient" I was mainly speaking about speed of execution, although speed of development/maintenance is always important. Fast/efficient means (generally, and in my case) be able to handle thousands to tens of thousands of simultaneous users on a single web server. Which I currently can handily do with no problem.
By saying "scale well" I realize that I am addressing a different skill set and cracking open a completely separate set of topics, but in general I was targeting the frameworks with that phrase. If a framework already has features baked-in for horizontal scaling then that would be a plus.
In my experience, Windows servers are always more expensive and often require a bit more horsepower (CPU and RAM) to get similar performance. Not only that, but (again - in my experience) I must then add additional solutions that generally cost more in a Windows server environment (WAF, firewall, monitoring, etc.), and which can often be had "for free" or low cost with a Linux solution.
As for your comment about "basically any language/framework will check this box," I would respectfully disagree. Although I am far from feeble-minded, I am - as mentioned - older. And even though I feel that I am as sharp as ever, growing older brings a certain resistance to change. It's not that I CAN'T learn new things, it's that I DON'T WANT to spend a lot of time and frustration making the change. If you are saying that all languages and dev environments have a similar learning curve (which I doubt you were saying) then I would have to disagree based on real-world experience. Learning APL and Lisp were very different from learning Databus and COBOL and Pascal. Learning C++ is very different from learning Cold Fusion. Etc.
But your points are well taken. Perhaps my questions are simply too broad. I was just hoping to open a discussion about tools and frameworks that people have found to be fast-executing, relatively easy to pick up, and which might bring a certain amount of joy back to web programming and getting things done, rather than being mired in minutiae. As an example, I've just seen a recent post here on Sveltekit/Svelte, which I am now researching. As another example, I've frequently heard people attribute a certain amount of happiness or joy to using Ruby/Rails.
That sounds nice.