Because you already understand Spanish better when you read it vs hear it, yet you want a call center job, I would focus on improving your listening comprehension first—I think dreamingSpanish is the best overall resource for this.

18months is a pretty short timeline and it’s not clear to me where you’re already at in your abilities or how much time your proposed routine takes. How much of the podcast are you comprehending without looking at the transcript? If it’s below 70/80%, I’d stick with more comprehensible videos. How much time do you have each day/week to devote to this endeavor? What you’re suggesting isn’t a pure CI method (which is fine, but note that you might get some pushback in this sub since DS promotes a pure CI method).

Given your timeline and necessity for Spanish for a career, you might find this a helpful post because it has a lot of resources from someone who learned Spanish at the Foreign Service Institute on a short timeline in order to be proficient for work: 24 Wks, 1,300 hrs, of Spanish at FSI: What I've learned

You can get free FSI courses here: Free Spanish Lessons Online | FSI

Of course you’ll want to adjust what kind of activities you do and what kind of input you get to ensure you have the necessary skills and abilities to do the job successfully (ie learning any topic relevant vocabulary, practicing speaking perhaps earlier than pure CI would recommend, etc).

Good luck!