Bad Harmonic Balancer? Idler pulley? Charging malfunction error

[michaelw9]

Hey y'all, hoping some one might be able to help me out and confirm what might be the problem. 2015 M4, Jun2014 build, 21k miles. A couple track sessions and driven hard here and there but nothing major. Most of the time the car is just sitting, recently last 2 years or so outdoors without any garage unfortunately.
I needed to move it so went to jumpstart it as the battery was dead - that's what happens when it's been not turned on for 3 months (I know, I should get a trickle charger). No issues or symptoms at all the last time I drove it on Xmas.
This time I had it jumped but wasn't able to start it - brief clunk noise, it didn't even try to turn, and got a charging error malfunction, drivetrain error messages, a few others. Did some looking around on some past threads and a few seemed to have idler pulley issues. I haven't had anything mechanically go wrong with the car since New and it's been almost 10 years, so not unexpected by now.
Looking closely under the hood, it looks like what I see as the rubber seal part of harmonic balancer is torn apart, if I'm seeing it correctly. The belts all look OK. I can't really see the pulley. I'm good at doing basic maintenance and doing my oil changes myself so if it's relatively easy DIY seems it might not be difficult to replace, except that part is quite expensive compared to the pulley , about $600 to $800 depending where it's listed. I haven't seen any other threads with anyone having issues with the harmonic balancer, just the idler pulley.
Am I seeing this right? Tried to get the best photos I could, it's a tight squeeze in there and the sun wasn't helping, but also impossible to photograph in the dark.