Swapping tokens for ether help

Hello, since I cannot find a legit site to lookup liquidity for a smart contract this is my only option. Like there isn’t a single site that you go on, paste a smart contract option and it gives you all the liquidity given to that token so I know what I can swap for at the best value.

My question is, how do I get the exact or close to exact value for a smart contract token. Like if metamask, bscan, zerion all these apps are giving me a value for the amount of a specific token, how do I swap and receive that amount in eth or bsc??

I’m guessing it goes off liquidity, if that’s the case, how do i check to see which coin is providing most liquidity for that contract so i can swap for that coin.

I’m asking here because theres swapTokenforexactETH tools and whatnot if that helps regarding being able to swap for amount shown in wallet ill do it.