You do need to look at the code because it will tell you how KYC info is being passed. LN is online now and transaction fees are now almost zero, not the $20 that you suggest.
The exchanges are of course centralized but you don't have to use exchanges at all. You can just use a hardware wallet and accept payment for services. You can also run your own lightning node now and be one of the pioneers in decentralized trading. Coinbase and others like it have always been banks and Andreas Antonopoulos explains you should steer clear of holding coins on an exchange.
If you have your own hardware wallet, you've become your own bank.
Do you need Bitcoin to get on the LN? When you transfer Bitcoin to your address, how much does it cost? $20. Yes, once on the LN you can trade without fees, but ultimately for anyone to cash out they have to go back to Bitcoin, and get zapped with another $20 charge as a fee to send to your address, as sending just means putting your transaction in the blockchain, and that is not free.
You must be using an exchange or non segwit address. This is what I'm seeing with my hardware wallet using various confirmation speed settings...
I'm seeing fees between $3.84 and $0.12 depending upon how fast I want confirmation. BTW, it's exchanges like Coinbase that wanted SegWit2X which failed. They were accused of spamming the network with transactions to keep tx fees high.
It's Sunday afternoon so maybe the fees are lower than midweek...