Thanks for the quick input. The onward domestic would be the last nonstop of the day to my final destination (my home city). Wondering if I just proactively plan to overnight at an LAX airport hotel (would have time to go out on the town for dinner which could be nice after the long flight from Japan) and then fly onward to home the next morning. That probably wouldn't be bookable as a single itinerary though given it would be something like 18 hours layover?

There is no need to plan on spending the night at an airport hotel.

I never check luggage and travel only with carry-on bags. I have Global Entry. It has never taken me more than 15 minutes to get from plane to curb when arriving at LAX on an international flight. If you have checked luggage, add approximately 30-40 minutes to get your bags. Walking from TBIT to T4 takes no more than five minutes. Add five minutes if your flight to your home town departs from T5.

Unless your flight from Tokyo is late, you will comfortably make your connection.

This is very helpful, thank you! Will proceed with this plan.

Yup. With no checked bags, it takes as much as it takes to walk non-stop from gate to connecting flight.
Add perhaps 2 min for stopping at the GE kiosk and perhaps 5 mins to go through security at flight connections. There is a dedicated security check point for connecting pax that is different from the security checkpoint for non-connecting pax dropped off at the curb.
I usually see nobody going into the flight connections (to the right). Always seems empty.

The transit security checkpoint was closed for construction last time we went through in January.

There was no line at TBIT Pre-check.

The question, is, is it open now?
January is an old data point considering the ever changing construction status at LAX.
But yea, TBIT precheck is usually empty. The one at T4 not so much.