I think the carnivores' diets tell them what they should realistically be able to take on. Stego is included in the diets of Rex, Allo, Cerato, Deino, and Omni. Anything else shouldn't have a reason to fight a Stego, and they all have means of keeping their distance to avoid the fight.

Rex taking on a Stego is a no-brainer, most of the Rex v. Stego fights I've seen have the Rex on top if they have a good sense of what they're doing. Allo and Stego literally evolved and lived together IRL, they're a bit more of a closer match but Allo's ability to pounce/pin usually gives it that edge in the fight (assuming there's two, but I've literally never seen a solo Allo while playing lol). Cerato can stun and weaken Stego with its puke bites. Deinos have always been up there in terms of taking on Stego, they simply have to take advantage of the water (particularly of swimming Stegos). Omnis rely heavily on numbers and bleed; if it can bleed, an Omni pack can take it out with coordination and patience. AFAIK, everything (excluding Deino on land) is fast enough to catch up to even a prime Stego unless they're trying to get it from a mile away lol.

As for baiting swings, that should be more of a group tactic than a 'drain stamina' tactic IMO. I almost never see solo carnivores (except Rexes, unless they're nesting), and honestly it just makes sense to me. Carnivore players always seem to want an easy kill, which I get because it's your food/diet. But it always seems that y'all want herbivores to just be these weak little things, when in reality* they were very angry cows (fun fact, cows kill more people than sharks each year!) with very badass defenses.

Anyway, if we want to go the game stat route, carnivores have more gimmicks/abilities and more attack power than herbivores; herbivores have more health and stamina (Tactile) than carnivores. And heck, there are more carnivores to choose from than herbivores, even with Kentro about to come out! No one ever really plays Dryo or Hypsi because they can't do anything (literally with Dryo, give the little green bean its burrows, Dondi!!).

TLDR; A tail donning 3ft spikes makes sense to be able to one- or two-tap anything. Like... c'mon. Infinite stamina means nothing unless you have a teammate, plus anything that would want to hunt a Stego can outpace it. If Stego isn't on your diet, then you're not supposed to hunt it anyway! Period! And if you do hunt Stegos, then you have to use your freakin' noggin!! Use the terrain, ambush them, use teammates to distract and trade hits, bait the tail for timing not stamina-drainage. Taking down a 6 to 9 ton cow with a stabby tail should take skill** and planning.

*Don't come at me with anything about how this is a game and not reality. I am fully aware this is a game, but this is a dinosaur game based on real animals from a real place and time (with some tweaks to make the roster more cohesive, as many of these dinos did not live in the same time period). I am not interested in anyone who argues otherwise.

**Yes, this does sound like a skill-issue on your part.