Not to worry.
A 7700K will slow down or turn off if it senses a dangerous temperature.
That is around 100c.
80c. may be higher than I would expect.
What is your cooler?
If it is mounted well, I would expect to see 10-15c. over ambient at idle.
What is your case and fan arrangement?
Any cooler needs a good source of fresh air to do it's job.