"Dieselpunk" is sometimes considered the next door neighbor term for WW1 through early 1950's retrofuturism with electricity and radios/very early televisions.
Sometimes people use "Steampunk" for shorthand for both because there are some overlaps in either direction, especially if you are trying for "just" pre-WWI retrofuture. Though I think the above poster was maybe especially trying to highlight the sort of pre-WWI overlap with Steampunk with more electricity but not yet as many cars and "diesel".
I don't know. Steam and electricity seem more like a coincidence that they were developed at the same time, so worlds without one seem natural. Another possibility might be no semiconductors. No nuclear also feels plausible, but it's just not interesting. Anything else requires a massive stretch to explain why technology got stuck in such a state.
Perhaps, if you are worried about realism from the perspective of modern technology. But a lot of the concept of retrofuturism is considering the possible futures from the perspectives of the past. You don't necessarily need realism for why you would consider an exercise like that.
Steampunk is "rootable" in the writings of Jules Verne and H. G. Wells and others. We have scifi visions from Victorian and Edwardian lenses. It wasn't needed at the time to explain how you steam power a submarine or a rocket ship, it was just extrapolating "if this goes on" of quick advances in steam power and expecting them to eventually get there.
Similar with a lot of Diselpunk. The 1930s through the 1950s are often referred to as the Golden Age of scifi. There's so much science fiction written in the real world with a zeal for possible futures that never happened. We don't necessarily need a "massive stretch" to explain why technology took a different path or "got stuck" at a particular point. We've plenty of ideas of the exuberance of that era just in the books that they wrote and published themselves.
(Not that we are lacking in literary means to create excuses for the "realism" of retrofuture, either, when we care to. For one obvious instance, the Fallout franchise's nuclear warfare is central to its dieselpunk setting and an obvious reason for technology to get "stuck". For one less obvious reason, I like "For All Mankind" and its "Apollopunk" setting using the excuse of Russia beating the United States to first boots on the Moon and the butterfly impacts that could have had.)
I mean that steampunk looks plausible, because it indeed seems to be purely a historical coincidence that electricity was developed at the same time. They are unrelated, one doesn't follow from the other in any way, so there is no obvious need to have both.
You pretty much need to have both chemistry and electricity, or neither.
Even Jules Verne understood the impossibility (or at least absurd impracticality) of a steam powered submarine, and made Nautilus electric.
It's unclear if internal combustion engines would be developed without electricity, and to what degree they would become practical.
I'm not sure about semiconductors, but the discovery does seem fairly random, and it seems plausible that electronics could just go on with vacuum tubes.
It seems perfectly plausible that nuclear wasn't noticed or practically developed, but, as I said, it just isn't an interesting setting.
Sometimes people use "Steampunk" for shorthand for both because there are some overlaps in either direction, especially if you are trying for "just" pre-WWI retrofuture. Though I think the above poster was maybe especially trying to highlight the sort of pre-WWI overlap with Steampunk with more electricity but not yet as many cars and "diesel".
https://en.wikipedia.org/wiki/Dieselpunk