Since you’re “new” to this PC buying game I highly recommend you watch all 4 parts of Linus Tech Tips’ “Secret shopper” prebuilt PC buying series. It will go through every bit of what to expect, what to ask as a buyer and what not do when you buy a prebuilt PC. It will potentially save you up to several grands.
Now as a general rule of thumb when buying a PC for VR: just buy as much computer as your wallet permits. At least 32GB memory, at minimum 3070 and a fast processor.
This will all require a bit of work and studying what to get from your part - unfortunately. Don’t just blindly believe what people say in the forums, research yourself and double check recommendations from the internet review sites/videos.
Good luck!