Fond of your ar5e! I repeat, the whole mechanisms are under considerable stress, as you admit above twice, they are poorly made from rubbish materials. For the past 40 years, I have had an almost annual job of replacing or repairing our own valve actuators. Such was their unreliability, I had in mind to design something more robust myself, until I discovered MOMO actuators as a possibly more robust replacement for the spring return units - which is similar to what I had in mind to devise. Since then, zero failures - but let's see how long it lasts. I have a spare MOMO ready to put in, should it fail.
No springs in the MOMO, no motor powered up and stalled, none of the massive stress and extra heat generated. They just move the valve to position and stop.