Reacting to the first paragraphs: on decentralized exchanges, traders (liquidity takers) don't change the price because of something called the constant product formula. Liquidity providers do.

Since trading doesn't impact price, front-running can't be done by sandwiching buy/sell orders but with LP orders.

Also slippage isn't price movement due your own trading (that's price impact). Slippage is difference between displayed price the moment your press trade and current price when order is processed at exchange (due to network delays etc).