I have never heard of anyone wanting or getting an accurate time with a 555. Anything over 10 minutes is very imprecise. The chips I am mentioning use a very small capacitor and multiple stages of division to get up to 1,000 hours.
You have to start and throw out old technology, just like I have, and see what the Chinese have achieved.
20 for $2.20 posted. No programming needed. Just jumpers and 1 resistor. You cannot beat the Chinese.
You haven't mentioned if it is a micro or not and the output current capability and the voltage-range.