You won’t have to keep all your funds in a hot wallet. Splicing allows for channel size management, increasing or decreasing the size of a channel. You don’t have to settle all your transactions on the main chain, and likely most people in the future will never settle a transaction themselves on-chain ever. Scaling btc use will need lots of improvements like ephemeral anchoring too, but it will all lead to a world where you can keep most btc in cold storage and move it to lightning or other possible L2s when needed to spend. I’m certainly no dev or expert, but I have had the same concerns in the past, not anymore