Busted into this thread to recommend Let's Encrypt, certbot, and my favorite ways to authenticate domain ownership in containerized environments. Not those certs.
Only get the certification(s) you need to get the job you want. As someone who sometimes has to run the technical interview -- I will ask you if you have the cert we require for the position. Regardless of your answer, I'll then see if you can do the job (or can learn to do the job quickly based on similar experience).
If you have the cert but can't do the job, you're fucked.
If you can do the job, but don't have the cert, I'll tell you to get the cert ASAP.