P0299 Code And others?

Hello everyone, I am an owner of a Chevrolet Duramax Trailblazer 2.8 LT Engine, Automatic transmission, it has 65,000 Miles or approx 105,000 KM on the odo.
I would like to seek your advise regarding the recent problems

1. Two weeks ago my alternator pulley cracked, the spring inside the pulley 'flew' around the engine. Therefore causing multiple 'damages' to the aircon's high tube.
The following day, I had the pulley, high tube and freon topped up. Here's a picture of the damage before it was repaired.
Before the alternator was repaired, the battery were not charging.
Hood Automotive tire Automotive lighting Sleeve Gesture

2. Since I was reading the vehicle's manual, I decided to 'change' the supposed lifetime ATF fluid by performing a drop-and-fill. Apparently, there were no visible damages to the transmission, I was assuming the crude found sticking to the pan's magnet were the magnet itself or regular wear and tear. This si the first time I changed ATF.
Motor vehicle Automotive lighting Bumper Automotive exterior Automotive tire

3. Decided to change the serpentine belt as well, for the first time (guys gotta change the belts, as the old one I had extended by 1.5 cm). Circled is the old 'extended' belt.
Tire Automotive tire Wheel Vehicle Alloy wheel

After all the changes done above, I test drove the car for several miles (up-hill, downhill but no highway). And I can safely assume, my job was well done.

4. I decided to crawl under the car to perform a visual checks (same evening as the activities above), since the alternator spring may have potentially caused damages to other rubber hoses within the engine, and this is what I found connected to the turbo charger (though I do not think this was caused by the spring). The hose (marked by a red line) is connected to the air-intake/air filter housing. Parts of the hose also melted or maybe chewed by critters (there were 'black powder' materials, was assuming the back power were caused by the rubber hose being chewed)
Automotive tire Hood Helmet Automotive lighting Motor vehicle
Thinking, this is a usual wear-and-tear, I decided to test drive the car yesterday in highways.
ALAS, after 30 min or so, the car started jerking and my max speed was 60 Kmh (I managed to hit 100 kmh, several minutes before), and I was assuming I was in limp mode. Initially, I had no issues with upshift/downshift (it was in fact, unnoticeable after the ATF Change).
I then connected my bluetooth OBD2 to watch the RPM graphs and manage to obtain fluctuating graphs below 2 rpm while driving home.
Also I heard 'intermittent' cracks/sucking of air noise closer to the passenger seat (that's where the turbocharger is located).
I got home safely, did an OBD2 scan and were given a P0299. Now, I've ordered a replacement hose.

Initially, I thought I had
A. Transmission issue as I had minor slips before the ATF were changed (there was once my RPM had a trajectory to 3/4 RPM before it changed to 4th gear)
- Reason I changed my ATF. Also I crawled under the car, had my dad floor the gas and did not hear and 'odd' noise in the transmission.
B. I am assuming the last item (4) was causing the P0299. The noise I heard at the passenger seat were "sucking" noise by the turbocharger.

Has anyone ever experienced this before?


Sorry for the long post. Thanks