Nobody here can truthfully claim your system is stable. It is not sitting in front of them. It is sitting in front of you so only you can tell us if it is stable.
So is it? Does it suddenly lock up? Reboot? Shut down? Stutter (in audio or video)? Throttle back in speed? Display artifacts? If the answers are "no" to all those, then your system is most likely stable.
There's nothing wrong with your temps. Even 50°C is fine. What matters is your temps when your system is tasked. So as suggested above, play a demanding game or perform the tasks you regularly perform and watch your temps.
So how do you watch your temps while using your computer? I use and recommend
Core Temp for that.
It doesn't have to be perfect. You just need to make sure there is not a blanket of heat trapping dust covering everything, that the fan vents are clear, and your heatsink fins are not caked with dust.
I do NOT recommend changing the TIM (thermal interface material) on your CPU. If yours was bad, even your idle temps would be bad. And TIM does not just go bad. It can easily last 5, 10 or more years AS LONG AS the cured bond between the mating surfaces is not broken. And that does not happen unless the cooler is removed, or the computer is handled roughly. If you "
need" the few degrees a fresh application of TIM
might provide to keep from crossing over thermal protection thresholds, you are already too close to those thresholds and you have other, more urgent cooling issues to deal with first - like case cooling.