There are a few factors to consider when choosing a cooler for the Ryzen 7 3700X. The first is compatibility with the CPU socket. The second is airflow and cooling capacity. And the third is noise levels.
The most important factor is compatibility with the CPU socket. The Ryzen 7 3700X uses an AM4 socket, so any cooler that supports that socket will work. Some coolers come with mounting brackets for multiple sockets, so they can be used on different CPUs.
Airflow and cooling capacity are also important factors to consider. The Ryzen 7 3700X has a TDP (thermal design power) of 95 watts, so you'll need a cooler that can handle that much heat output. Coolers with higher airflow and greater cooling capacity will be better able to handle the heat from the CPU.
Noise levels are also something to consider when choosing a cooler. Some coolers produce more noise than others, so if you're looking for a quiet PC build, you'll want to choose a quieter cooler.