As a buyer, I dont think that you need a real estate agent. Essentially, one is as good as the other. They ALL work for the seller.... The seller is paying the commission. The agent works for them.
Some will claim to be "buyer's agents". But, they are "agents" and in the end represent the seller.
This is not true of the most recent state in which I lived, where a buyer's agent, by law, has a fiduciary duty of loyalty to the
buyer. However one could be cynical about this, because the buyer's agent is paid by the seller's agent (so the services are allegedly free to the buyer). Also, the "buyer's agent" must disclose known adverse facts such as the buyer's lack of creditworthiness, to the seller's agent. CA law is pretty similar. So, to an extent the answer to the OP's question depends on the state involved.
On the subject of surveys, I think that could be skipped if it's in a platted development. If the property lines are defined by "ways and means" or "metes and bounds," the survey could be worth it.
Personally, I would not hire a buyer's agent if I had already found the house. I
did hire a buyer's agent for my last (and I do mean LAST) house
search, and was glad I did; he did a good job. To reward him, I attempted to use him on the sell side and he was terrible, and I fired him (I had refused to sign a 90 day exclusive so some people might argue that's why he was terrible, but that wasn't it).