What's your definition of L2 that include centralised entities?
There is no central authority in LN. There may be "hubs" which are more or less important, but that's not centralisation because there are several of them, it can also work without them, and also they can't steal your money.
Would you say that email is centralised because there area few big server (Gmail, Microsoft)? But even if it may more convenient to use one of the big server, you still have the choice not to use them.
With LN you can have a private channel with your friend and do unlimited number of transactions with (literally!) 0 fees. Thanks to recent developments it's also much easier (and cheaper) to then swap those BTC to onchain - sometimes even cheaper than a comparable single onchain BTC transactions.
