There are still things to be done in order to make using L5 with external screens more efficient. Compressed buffer formats will be one thing that should reduce memory bandwidth significantly, another one is TS buffer sharing, which is already in works:
When it comes to charging, the thing is to have peripherals that can provide enough current at 5V. I’d say that you need at least 2A to charge when using an external screen, and having 3A would give a comfortable headroom - that’s what Baseus dock negotiates here for me.