Yes, deactivating unneeded background programs can save some temps and CPU stress. I had one recently that kept my HDD rambling and 25% CPU use. That is one core constant active. Sometimes programs do not close completely or continue searching for something that is not there.
The high temperatures might be related to the Indian Summer we had this year. But over 50 degrees idle is too high.
Other defects can be a faulty voltage (pump) regulator, a loose contact or a malfunctioning temp sensor.
Just keep an eye on it for the next couple of weeks to see if the issues persist.
PS I do know people who disassembled AIO waterloops, exchanged tubes for more fancy ones or even extended a loop with a GFX cooler or extra radiators. And you can use pre mixed coolant.
Only problem is topping it off, without air bubbles in the loop. Best in a sink or bucket.
It is the last thing to do and i would rather buy a new one, as they are not that expensive.
PPS, i have that a lot, not knowing anymore where the hardware came from.