Good day! Sorry that I didn't know you had replied on Friday. You replied to yourself in your last message that day, so I didn't get a flag notification.
I'm sorry that nobody chimed in to help you in the mean time.
I looked at the log_ab file you posted. It's a bit convoluted in my humble opinion. First off, it's incomplete and begins at then end of some FW update attempt in the past. Also, there are no dates showing at all which is unusual and frustrating for troubleshooting. That being said, I'm not sure how reliable the data is but I did see a couple of things.
It looks like the file begins with an update from v1.3.2 to v1.4. That is followed by an update on an additional battery (module 11) to v1.4. Then later, using a different SD card, there was an attempt to downgrade FW from v1.4 to v1.3.2, but that gave the infamous module 8 and module 15 "device not detected" error. Re-attempts gave the same result and error.
[00431762][15 00][00] device not detected.
[00444627][08 00][00] device not detected.
Historically, getting a device not detected for these two modules most often means a bad gimbal main board (video chip bad or FW corrupted). Especially on a P3P which is more susceptible to overheating during a FW update if there is no external house fan or some other external source of airflow during the update process. You can find lots of posts on here about the 8/15 device not detected error and bad gimbal main boards.
All that being said, 8/15 "device not detected" normally presents as a loss of image (no image transmission) even when everything else seems fine. Most people are able to do everything else such as connect, start motors. fly, record video, etc. They just have no FPV image showing on their mobile device. You may have that issue later, but right now you have a different issue. No connection.
What makes your situation hard to troubleshoot is that between v1.3.2 and v1.4, DJI completely changed the process for updating RC firmware. It seems that your AC and RC have FW from around that time, so it's hard to tell which process you need. They also then changed encryption between AC FW 1.7 and 1.8 which further muddies the waters since both the AC and the RC need to be either pre or post encryption change, so knowing which version is on each becomes very important.
If I were you, I would first try to install v1.4 on the AC and look at the result file. If it says, "The firmware on the SD card is identical to or older than the current firmware on the aircraft," then try a later FW version. I'd say try v1.6 or v1.7. Skip v1.5 because it was known bad and don't yet go to v1.8 or later since it is the new encryption. Then check the result file again. Sometimes FW installs take a long time and also sometimes make horrible noises. Don't be afraid to let it continue (using an external fan) but if you are in an office environment you may want to try it somewhere away from people. Maybe even take it home.
Click here for the most referenced steps for updating FW, and there is also a link to download
older FW versions directly from DJI.
Good luck!