I will be honest with you. I've never met a shredded person in my life that's on a keto diet. I've met lots of overweight people who "say" they are doing it, but I've never met anyone that I would consider to be in shape that says they got that way from a ketogenic diet. Maybe it's just the people I've encountered so far, or perhaps it's just that a keto diet is not sustainable over the long term.
I follow probably 20 fitness personalities on Instagram and they post what they eat frequently. Not a single one of them posts pictures of plates made up primarily of just protein and fat.
I'm not going to be an advocate of Keto diet. I tried it once and lasted about a month or so, I could stand it and I couldn't lift wights while on it. It is hard to sustain this diet knowing how many great food items you have to skip (i.e. most fruits)
But this diet does make a lot of sense. You can't burn fat in the presence of insulin. And don't confuse whether it "works" with "fitness personalities". I could go on TRT now (like most of those male "personalities" you follow) and not even worry about keto, yet I would quickly go from my ~20% body fat much closer to 10. That's the increased metabolic rate affect from TRT.
Also, you can "get there" in many different ways. You can lower calorie consumption and up aerobics and finally you will get there. But the question is how much do you have to starve yourself (you have to in order to be in negative territory) and how much (what kind, how long) aerobics you need to do to "get there". Just see how much prep work is done for the competitions and how much lean tissue they need to lose because of that starving!
To beauty of keto is that if you lower fat intake to get to negative territory, you will burn your body fat without much exercise at all.
It should be pretty obvious, that once you "get there" (whichever way) then it is much easier to "stay there". You can eat whatever you want as long as your overall calorie consumption does not exceed your body needs.
And finally, it would be beneficial to narrow down the definition of "shredded". What kind of body fat % are we talking about here. About 8-10% is pretty much the most you can get (sustained). Anything lower than that it temporary for the competition (at the expense of lean mass) at least you're juicing heavily.
I'm just tired of all those fitness "personalities" giving advices to others. First thing they should say/proof is whether they are juicing (including TRT) or not. I have no problems at all with gear, it's just makes it a different ball game for each and every aspect of it, including diet, exercises, stamina, determination and motivation.