There are different methods to achieve such a form, and each of the shown examples certainly has it's merits. But only Misoversaturaded cared about a quad-mesh, and that last method was probably the fastest. In some of the other examples I saw some areas that certainly pinch, especially with a reflecting material.
Now I didn't have the time to do a mini-tutorial about my simple approach, which took me a bit more then 5 minutes and has a polycount of 412 (of course it has a subdiv modifier); just boxmodeling as usual, cube, make the down poly less wide, create an edge in the middle, catmull the upper part, connect the dots with the down part, catmull, bridge after pushing the polys into a circle (there's a script for that I couldn't find anymore) and create the "hole", putting in some holding edges, and that's that (sorry, no minitut because I couldn't even write the first sentence here without being interrupted twice and that was more than 5 hours ago). I know, it's not 100 % the same form as rick intendend but it's something I will use later on myself for a seal ring (don't know if that's the correct word, just checked with deepl and that gives me the same result with the alternatives "signet ring" and "sealing ring" (somehow the latter ones make more sense).
The beauty of a subdiv modeler like Cheetah is that you can keep the polycount quite low, therefore can change or refine as much as you want, and if it still doesn't seem round enough, you just increase the subdivision. And most of the time it's quite fast as soon as you understand the form (that said, spline modeling is more accurate).