You didn't say which AMD CPU you have. And those don't sound like overly high temps - to me... According to AMD, the Ryzen 7 1700X, which is one of various AMD CPUs Dell installed in the Inspiron 5675, has Max. Operating Temperature (Tjmax) = 95°C Reboot and start tapping F12. When that  menu opens, select option to run Diagnostics and run the fan tests.
I have disassembled fans and cleaned but according to my AMD program the heat is building. When I run a couple of programs such as Firefox and Farcry it sends the heat in to a higher centigrade such as 64. What is going on? The fan speed increases to 582. With me running this Dell Community it has increased the temperature to 70 Celsius.
Over heating Inspiration 5675