Hello Henry,
Welcome! 350-401 is a requirement yes. You can book the lab without passing 350-401, but you won’t get the CCIE certificate until you pass 350-401.
I’m not sure what the best option will be to learn DNA Center. I did some research and found this article where someone got it running on ESXi. You need 56 CPU cores and 256 GB of RAM so that’s a lot. Cisco might release a virtual appliance someday.
For now, the only way to play with DNA Center is through Devnet or Dcloud.
Rene