The Twitter acquisition wasn't funded by venture capital, so your question about VC approval doesn't apply.
If you're using VC as a general term for "investor" (inaccurately), then the answer to your question is that the major investors, such as Larry Ellison and the Saudi monarchy, wanted political control of Twitter, which meant that they did (apparently) approve what Musk did with it.
You're missing the point. It matters little where exactly money to pay for acquisition of Twitter came from. What matters is that nobody expected Twitter to lose employees and users in such numbers. So, whoever gave the money, was still limited in ensuring the results are "fully enough" in line with their wishes. Because money is always finite.