Is there a single webpage that lists the current transaction fees for the major blockchains, like BTC, ETH, solana, avalanche, matic, BCH, BSC, etc?
I don't think it is possible to create such a comparition. Transaction fees change when the number of transactions on a given blockchain changes. It may be a greater or lesser amount at any time.
When it comes to Bitcoin's blockchain, the current fee status can be checked on the website:
https://bitcoinfees.earn.com/