I vote for #1. The short hop on BA intra-Europe J is totally fine and doable, and i love flying LHR-LAX or the reverse. I’m not a big fan of doing a long haul followed by a second long haul or a transcon. When i used to fly AUH-LHR-JFK regularly, I would try to build in a layover in London, or at least enough time to take the train to London for a meal, to break up the back-to-back longhauls.