This is such a toxic combination, becuse it requires significant people skills to get out of the "the kid who learned everything here and is grateful for it" and get proper respect as a professional. At some point the only option is changing jobs. I've seen companies matching your offer, finally realizing you actually have value in the market, but don't count on that, don't bluff.
I too ended up as the "go to guy", partly because I had a lot of enthusiamsm for my new job, and partly because the talent pool there wasn't very deep (or maybe they were smarter than me). It's fulfilling until it becomes unrewarding, I had to move on after almost 5 years. Still did consulting for them ocassionally for a couple more years.
If you have golden handcuffs and multiple promotions out of being Sarah, what is it costing you?
That sounds exhausting to say the least.
It’s very easy to turn into the Sarah - or the Brent if you prefer the Phoenix Project analogy. As exciting as it might initially be to be the go-to person, it’s also, as you so elegantly put it, “endless work, just enough authority to do current task, not enough respect/authority to solve the symptom”.
Best wishes! I hope you manage to turn it around.