uniswap needs to be upgraded and has a better wallet app than metamask. The current fees of the transactions are high, and they are not the solution for decentralized exchanges to exist. Other exchanges have done a better job of uniswap like pre-order, lower costs, and better interfaces. Uniswap needs to work towards those goals.
It is not problem of Uniswap, but of the blockchain what is built on - Ethereum. It is because it is decentralized - built on Ethereum smart contracts and currently there is a lot of transaction on Ethereum blockchain, so transactions are slower and more expensive, but everything should be fixed in next few months with the upcoming Ethereum 2.0 update.