The simplest and fastest explanation as to why using a tiny bit of thermal paste and expecting the CPU cooler to spread it evenly does not work anymore is because over time CPUs themselves have grown bigger in dimensions.
Do you need to change your thermal paste?
Thermal Compound Guide
How to Apply Thermal Paste: 12 Steps (with Pictures) - wikiHow
How to Apply Thermal Paste on CPU (Easy Guide)
How to apply thermal paste
My thermal paste just dried up completely. Is it necessary to have or is this what has been causing my pc to crash randomly? Lastly does it damage anything if I run
How To Apply Thermal Paste (Best And Worst Practices)
How to Apply Thermal Paste to Your CPU
How to Reapply Thermal Paste on Your Graphics Card to Improve Performance
Liquid metal vs. thermal paste: Which CPU compound is better?
How long does Thermal Paste last? (Applied and Stored)
How to Apply Thermal Paste - Intel
Can I still apply thermal paste even if the CPU fan has pre-applied thermal paste? - Quora
Is thermal paste supposed to cover the whole CPU, or is it fine if it covers around 50%+ in a circle/oval fashion in the middle of the CPU? - Quora