Revisiting lightning network after a few years

So I was introduced to the concept a few years ago. Always seemed like it was 18 months away. Havent spent much time looking into these things over the last years but decided to take another look.

I was impressed by how far they have gotten but also a little suspicious. Hope you dont mind if I post my questions here. Think of me as a 10 year old. The simpler the better.

1) custodial lightning wallets (ex Bluewallet). Sending from a Bluewallet to another Bluewallet you just use the companys accounting software. I.e. No on chain no lightning?

2) Sending BTC to Bluewallet you must pay on chain transaction fee of lets say usd 10?

3) sending from bluewallet to another custodial lightning wallet. You use lightning network and pay the channel fee that the channel owner has set (very low)?

4) using non custodial lightning wallets you must open your own channel to lets say bluewallet? How much in USD does it cost today to open your own channel? Is there any difficulties keeping it open with ”modern” user friendly wallets? Are you the only one that can close it or can bluewallet close it aswell? Why would anyone want to close it when it is opened?

5) using none custodial lightning wallets you have to send btc on chain from exchange and pay lets say usd 10 i tx fee.

6) using none custodial lightning wallets with a channel to bluewallet you can send to another custodial or none custodial with a channel to blue wallet but you then have to pay the channel fee (very low) between those parties.

7) does custodial lightning wallets give you your ptivate keys to the lightning wallet?

8) is there any good site that tracks the number of users of custodial and none custodial lightning wallets?

9) it seems you cant really get around paying on chain fee somewhere unless the exchange open channel to custodial wallet?

Alot of questions but that is lightning for you. Dont expect anyone to answer all but maby pick one question?

So custodial lightning wallets and exchanges becomes something similar to banks. BTC becomes new fiat system with the only difference being noninflationary... maybe thats ok to but bch is just easier and has no banks.

Cheers!