I guess dishwasher years are like dog years. At least it definitely behaves like a teenager at 2 years old, finishing when it wants to finish. Estimates be damned.
It actually is. Fixed length cycles haven't been a thing for many years now - modern washing machines adjust the washing cycle length by the weight of the laundry and its behavior during spin-drying, both its vibration behavior aka weight distribution (that can have multiple adjustment cycles to achieve reasonably even distribution) and how much water it loses - when no more water comes out during spinning, it will cut the cycle short to save energy.
If it says (e.g.) 43 minutes, but sometimes it takes 40 and sometimes 49 or 53, set your timer for 60 minutes and get on with life. Your laundry sitting for 17 or 7 minutes isn't the end of the world. If your timer goes off and it's still not done, set it for another 20 and do something else.
Of all the things to fill your head with worry and annoyance with, laundry is near the bottom of the list for me.