Can you describe it with a practical example?
For example, I want to buy something in Amazon using LN. Where do I connect to, to a random channel or directly to Amazon? how do I know if I connect a certain channel it will re-route to Amazon and other places?
In practice, it'll be simple.
You can open a channel with yourself to start with. No need to lock yourself to anyone.
Then, the wallet software will dynamically open channels with whoever you need to transact with. The option of choosing specifically who to open channels with can be done, but it won't be as quick or efficient as using the wallet software to route the transaction for you.
Im not sure about this... it would force me to make transactions as big as possible, even if I want to buy something worth $40, depending on how crowded the mempool is, I may consume a big chunk of these $40 in fees... and I don't feel confident having big sums of money outside of my cold storage, I would like to get out only what im going to spend but I dont see a clear solution to this, LN forces you to fill a decent amount, like $500 with current fees I guess would be a decent amount to spend on smaller purchases and would last for a while until you need to refill again.
"Force" is the wrong word. You're right though, there's not much point in adding BTC to a channel just for 1 purchase, you should fill it with as much as you're happy with so you can make multiple purchases from 1 channel. That way you can take advantage of the Lightning's fees, refilling channels with on-chain transactions should be kept to a minimum if you don't want to pay too much in fees.