Physician here (not in sports medicine, just a lowly pulmonologist). The only performance benefits I could foresee from taking systemic glucocorticoids like triamcinolone would be the anti-inflammatory effects? Medina Spirit, the horse that won the Kentucky Derby in 2021, was busted for being given a different GC (betamethasone), in all likelihood for similar purpose.
Maybe there are some theoretical metabolic effect like increasing lipolysis (breakdown of stored fat into free fatty acids) and increasing skeletal muscle glycogenolysis (breakdown of stored glycogen into glucose) to keep your plasma glucose levels up, and thus keep you from "bonking". BUT that would all be at the cost of many countervailing side effects after repeated use over even a modest time frame. For example, I don't think of triamcinolone (or any other GC) as helping with weight loss: in fact weight *gain* is a well known side effect of chronic GC use, even at relatively low daily doses for several months at at time. GCs tend to make people retain fluid due to some mineralocorticoid effect, which stimulates the kidneys to hang onto more sodium and water. Same thing with effects on muscle strength: if anything GCs are known to cause muscle *weakness* -- just google "steroid myopathy".
Whole thing seems bizarre. Other than being cheap and easily accessible, GCs are inherently catabolic and inherently have vanishingly low affinity for the androgen/estrogen receptors so there's no little to no anabolic effects. I just don't see how there's much performance upside here.