Cushing's disease - how likely?

My 36-lbs beagle-foxhound mix has always have excessive thirst and panted more. For years, bloodwork through many ER visits (due to her history of foreign body ingestion) showed mostly unremarkable results.

Last year, a dog sitter I used while I was on my vacation incessantly texted me about how abnormal her panting and drinking were and brought up Cushing's disease. I ended up bringing my dog to the vet for other reasons. ALP/ALKP was high - 542 (Google says ALKP has low specificity for Cushing's), and she had (acute) pancreatitis, which we treated with meds. The vet suspected of enlarged spleen, but I didn't do ultrasound then.

A year later, today, we did annual blood work and urinalysis after she had been drinking even more water than usual, peeing as soon as she goes out to the yard. Cannot speak to increased appetite because she normally gets 4-5 meals a day in smaller portion (since she vacuums kibble). It's 100 degrees in Arizona now, but even for that, I would say she pants a lot more dramatically throughout the day and looks more lethargic than I would expect from the hot weather. Anyway, her ALKP is 839, even higher than last year's ER visit. Urine concentration is low (due to drinking), but kidney values are normal. Her blood glucose is also normal.

How worried should I be about potential Cushing's disease and if it is, how it would affect her life span?