I don’t know if you fully understand how public blockchains work.
There is nothing to export from Uniswap, it has no secret database somewhere on a corporate server. Its database is Ethereum blockchain, where every address’s full transaction data is public and available to anyone.
Of course, a web page could be created to show user’s Uniswap transactions. But it’s not what one needs for tax reporting. One needs all transactions for reporting period, be it Uniswap or any other Ethereum application.