What stat is better to look for in a processor when comparing it to other ones?

Trust me when I say this isn't an indictment against you it's one against the system but there isn't one answer.

The thing with processors is that generally the speed or core clock being higher is better, but then you run into how many cores there are. More cores is generally better. But then you learn that there are applications that only use one core, and you see that more cores generally means a lower clock speed and when you are working with a lower clock speed it means worse performance in an application which can only use one core- which would mean there are scenarios where many cores at a smedium clock speed would perform objectively better than a processor that had a single core with a high clock speed while there are also scenarios where many cores at a relatively low clock speed would perform objectively better than a processor that had a single core with a higher clock speed.

This is all also before you consider power consumption, form factor, memory clock support, and general market support.

TL;DR: Go to PCPartpicker or r/buildapcforme and start looking at builds that are recommended for your use case, and go backwards from there in learning why it is that those parts are recommended to learn about what stats you you should into.