Overheating Problem that doesn't go away no matter what I do :(

Hello! I'm trying to fix an 1932 Macbook Air from 2019, but I've been struggling with overheating. It heats up to 90-100 degrees Celsius on startup, then goes down to 30-45 on idle, after the fans sit in full blast for a while.

Whenever I do anything on it (like open a file) the temp immediately jumps up to 60-70 degrees Celsius.

Whenever I start a graphically-intensive process (like open a PDF with images, launch a browser, open multiple images, etc) the temp quickly jumps to 80-90 Celsius.

In both cases, it needs the fans running at 8000 rpm for like 10 seconds to cool back down.

I'm using Macs Fan Control to monitor the temperature, and I set my own automatic rules for the fans to kick in earlier.

Even so, the computer often goes into kernel panic due to overheating and restarts (can't use it for more than 1 hours without this happening). I can provide the reports if you think it'd help, the only common thing between multiple reports I've noticed is that the process responsible is usually kernel_task, though I'm not sure that adds anything.

Here's what I tried so far:

• Cleaning the insides of the laptop, fans, etc, it's spotless in there.
• Replacing the thermal paste.
• Resetting device, and reinstalling macOS
• Resetting the SMC

Replacing the thermal paste had an impact, it lowered the idle temperature from 40-50 to 30-45. But I still get the kernel panics.

Considering all the symptoms, What would you think is the problem? I can't notice any damage or problems around the CPU/GPU, and since the laptop functions, always gets past POST, etc, I'm not sure if it's a motherboard issue.

I was thinking the fan might be the problem, but that too looks fine on visual inspection.

My last recourse was to change the battery - I was thinking there might be a problem with its board, sending too much power to the GPU? Is that possible, should I consider it?

PS: Nothing comes up while doing Apple's diagnostics. Problem persists in safe mode, with no peripherals connected.