The year is now 2023, and there has been a proliferation of cryptocurrencies. You still need to ask a crypto exchange. You still can't see the dollar transactions whenever someone trades a bitcoin, on the bitcoin blockchain, so you don't know what they paid for the bitcoin.
But if you're willing to look at a different blockchain, you may ask a decentralized, blockchain-based crypto exchange, for example, the Uniswap V3 WBTC-USDC pool on Ethereum. As long as WBTC is still exchangeable for BTC, and USDC is still exchangeable for dollars, and Uniswap V3 is still a protocol that people use, you can assume this is the price people trade bitcoins for dollars on this platform. (If it very different from the bitcoin price, then someone would trade it and make free money. That's why there's only one price.)
You don't have to read it from the info.uniswap.org website - after getting familiar with Ethereum, you could read it from the blockchain. The information is still invisible to the Bitcoin blockchain, but since the Ethereum blockchain is working as a crypto exchange, the information about its trades is available on that blockchain.