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's not impossible to connect to all these blockchain to monitor transaction fees but I bet it will be tough and maybe costly to maintain. It could be prone to some bugs that will affect how price are reflected on the site
ulhaq, bookmark scanners or trackers for each chain. It may be inconvenient to open a separate tab but at least you'll be more confident it's up to date.