5GHz should be no issues for daily use provided you have a good CPU cooler and keep temps under 80 degrees C at max load like Prime95 and AIDA64. Gaming tends to put about 50 to 60 degrees C so never an issue.
It would also be good to understand what vcore you are using for your 5GHz overclock as anything over 1.35v is a bit too much for me persoanlly and most people recommend a hard cieling of 1.4v onthe 8700K...Still try to keep vcore at 1.3 to 1.325v and you are good for a long, long time...
I settled on a 1.278v for my 24/7 overclock at 4.9GHz on my 8700K and for 5GHz I needed 1.325v which is more than okay but I am happy with the 4.9GHz at 1.278v...