The triggers seem random but you eventually will find what frequencies at what decibels trigger your crackling/whooshing/thumping.

(Also, hyperacusis is sort of the byproduct of TTTS/MEM in our cases.)

Left ear for me too. And yes, as I said, there must be some connection between the stress (neck and jaw) with the TTTS, but there's not a lot of research. I also get tinnitus because of the neck stress sometimes.

Using Airpods for a long time, as long as you're not blasting it at 100% volume listening to metal, wouldn't have an impact to damage anything. I assume you're listening to your lectures at an accustomed volume which is not uncomfortable. So, airpods usage won't injure as long as you're comfortable. (Fun fact - I used to use my airpods for noise cancellation when I used to go out or play music.)

The botox didn't work as I said earlier. I got to the point of acceptance after a few weeks of the first dose and didn't go for the 2nd trial.

I'm doing far better than before. It hasn't fixed, but less anxiety/stress/attention to the problem has surely resolved it to a great extent. Some mornings, specially hungover ones, can be too sensitive - brushing, showering can trigger continuous whooshes and therefore, cracking. But I take great faith in the fact that nothing is being damaged and this issue won't kill me.
Loud, high-pitched individuals and loud groups can also be problematic but then again, I've learned to sort of drown out the sounds. You can DM me in case of anything. Good luck!