The high gas issue is that currently, the majority of DEXs use the Ethereum network. It is the auction mechanism and confirmation time that make people want faster transactions.
Currently, Justswap is a DEX based on the TRON platform and has a lower transaction cost. It resembles a copy of UNISWAP and is supported by TRON.
I believe there will be a lot of new blockchains that generate DEX and a much lower cost. Of course, those DEXs will appear in the future.
Then it's answered it already why it's only use low cost and fast transaction because this is only supporting tron blockchain .
Did I understand it right or they are also supporting any ERC20 tokens ? if they support ERC20 then how they actually can make them low cost if the eth blockchain is congested is its means the transaction need more time before it's confirm by the network?
Unfortunately, Justswap cannot do this as it only supports tokens on TRON's blockchain, and it doesn't have an ATOMIC SWAP function so it can't support ERC20. I know some DEXs support tomochain's ERC20 wrap and Serum DEX.
ERC 20 tokens will be wrapped on another blockchain and traded on that blockchain's DEX.