For Bep20 and Polygon, I think they are always stable even though there is an influence through the base price of the BNB and Matic coins, but always in accordance with the existing dose.
honestly this kind of stability in term of gas value required for making a transaction always depends from the platform itself, if the platform is kinda crowded i’m sure the fee gonna be rising high even if it’s other platform like matic that are being regarded as the true alternative of ETH all these newer platform just hasn’t faced the real issue of being overcrowded unlike ETH and i’m sure if they faced the same thing surely all these platform will definitely have some crazy gas amount required.
it’s all coming back with the platform itself, could they scale well or they just gonna become overcrowded and eventually leading the gas required increases significantly and sees if they could withstand the trends like NFT that could flooding the platform with so many NFT and NFT games transactions.