SEO Research and Determining What's "Worth it"

Hey all, I started a new job as a marketing analyst recently and my company is in the B2B SaaS industry.

Firstly, I am new to SEO. They are very SEO-focused, and specifically link building because that's what the owners built the company on. I have been tasked with researching new and current keywords and to determine if which are worth focusing our efforts on.

My question for you experts is this: how do I do that? Where do I even start? Like, how do I measure if a keyword is worth the squeeze? Trying to figure this all out and not feel imposter syndrome. Appreciate the help.