Over the past few years, I have been buying a little ether tokens, as well as BSC.
I have quite a lot of them and here I find a very expensive gas for transactions.
What is the cheapest way to exchange tokens (ETH/BSC/POLYGON) for Bitcoin?
Among the one you mentioned then polygon is the cheapeast. Eth has very expensive gas consumption if you used dex. But since you are gonna convert it into bitcoin, why not used centralized exchange since the payment is fixed. I dont think that fee will change there ad they have constant charge.
If using dex. Then pick polygon, its the cheapest one that give you small fee. But I think the best one is fantom.