I'm going down a similar route as you are. I'm sitting for the VCAP on Thursday. I'm more hands on but haven't had much opportunity to work on production systems yet. I've been doing the hands on labs from VMware. I've also taken the Troubleshooting & Operations course offered by VMware. Luckily my company took care of the costs on it, it was helpful. A lot of command line work and a good overview of troubleshooting methods.
I'd recommend going for it. Even if you don't pass the first time around, the whole process is good. I've learned more taking certifications and not passing than I have when I passed the first time :smileyhappy: Took a few attempts at my CCNP.
As far as study materials, VMware has a lot of good resources. The NSX administration guide and the design guide are good. Read the blueprint and go through each section. This guy has a good walkthrough on the blueprint:
https://thecloudxpert.net/study-resources/vcap6-nv-deploy/
Good luck!