The Certification math is easy:  More = better.  
However, what's even  better than the certs is having experience in the domain, with measurable outcomes to brag about.  The certs might get you into the interview pipeline, but ONLY real domain knowledge is going to get you through.

The BEST way to know about opportunities is to have personal connections on that team.  Start looking for people who actually work on that team and connect with them.  Build a rapport with them.  Ask them questions about the job, etc.

The SECOND BEST way to know about opportunities is to use ServiceNow careers page:
https://careers.servicenow.com/
Use it to find the positions you want in the location you're at.

Lastly, if you don't have personal network, make sure your resume and personal narrative is on its A-Game.
The hard reality of job search is that nobody cares how motivated you are.  They only care about capability, and getting the right person for the role.  Therefore you must express your experience as demonstrated capability that ACTUALLY DID SOMETHING.
BAD:  "Service Catalog"
GOOD:  "Created Service Catalog for <specific use case> that <provided what value>"

A good way to keep your narratives up to date and on point is to build a library of "XYZ experiences"
- "By doing <X>, I achieved <Y>, as measured by <Z>" 

Remember, as part of Expert Services, the only thing that matters is getting customers to success.  That means understanding what success actually looks like and being able to articulate successes from your past quickly, easily, and convincingly.