There are two types of engines for tp's
Free turbine and fixed shaft.
Their operation is different.
And if you over torque them it depends on by how much and what the OEM says to do.
It can just be a oil sample taken (SOAP) and prescribed periods or it could be the engine has to go into the engine shop for strip down.
Some aircraft do have limiting systems on them even though they are not FADEC.
But in general pilots are taught not to rely on them. Unless you were on approach you wouldn't have your hand on the power levers in turbulence. And if your on approach you wouldn't be anywhere near the top of the range.