So I don't know much about the 11th Gen Corolla, but here are my $0.02
Normal parasitic current drain on most cars is somewhere around 20 mA. This is the case of my 2018 Highlander and my wife's 2023 Lexus NX. Fluctuates between 20 and 30 mA, but usually stays around 20-23 mA.
Sounds like ECU-B is body ECU. It's the one that controls automatic door locks, power windows, dome lights, and things like that.
Question: Did you measure the current with door closed (locked) and waited a few minutes to make sure that all things went to "sleep". For example, the instrument panel "wakes up" when you open the doors, and takes some time to go back to "sleep" after you close the door. You should lock the doors, and wait at least 5-10 min before measuring parasitic current drain. Also, you should not measure the current immediately after reconnecting the battery (with the ammeter in series), because many things will "wake up" after sensing voltage again and take a while to go back to "sleep". So in order to measure the parasitic current, connect your ammeter first, make sure that everything is off, lock the door, and wait for a few minutes.

 

OK. So originally my measurements were made after about 10 minutes, with the door shut and the keyfob well away from the vehicle. I figured that was sufficient for anything to "go to sleep". However, I left it sitting while I broke for lunch and came out and it had dropped to about 22mA with a bump up to 50mA for about 20 seconds every 5 minutes or so. So apparently it just takes a really LOOOOONG time for this car to go to sleep.

So no parasitic draw. Ugh.... Something is killing this battery after about a week of sitting. The battery is only 6 months old. Alternator puts out 13.75V at 80A with headlights, defrost, full fan, full A/C. I'm kind of running out of options..

 

...So apparently it just takes a really LOOOOONG time for this car to go to sleep.

Hate to worry you... but the car never sleeps
Hours after the car has been parked in the garage, I sometimes hear a low running motor sound.
...It's the fuel purge system running a test...
But it never sleeps!!!

 

So here are some suggestions / questions:

• What is the battery voltage immediately after you turn off the car, with lights off and no other major electrical equipment running? It should be somewhere around 13.2 V immediately after you turn of the engine, and it can gradually drop off to 12.8-12.5 V after a while
• What is the battery voltage after the car sits overnight? It should be at least 12.5 V if nothing was left on.
• What is the battery voltage (voltage drop) while cranking? It should be no less than 10-10.5V

If the voltages are lower than that, the battery is not fully charged or weak.

- What is the voltage you measure at the battery terminal immediately after starting the car? It should be somewhere around 14.2 to 14.5V for a short time (from a few seconds to a couple of minutes, depending on the state of the charge of the battery), and then gradually drop to 13.8V.
It the voltage is lower than that, the alternator is not properly charging the battery.

 

Is this a smart key model? In the past, there’s been posts of the vehicle searching for the key fob and some owners reported a dead battery come the morning.