What crypto exchange has the lowest fees? OTC service as well

So far I’ve seen binance with .1% maker/taker fees and it has a lot of liquidity so low slippage, but binance US has lots of slippage. Or maybe a liquidity provider that can make up for fees with arbitrage. Also wondering OTC services with lowest fees/ bid-ask spread. Most seem to offer no commission but do take bid ask spread with non-concrete %’s