2018 A1990 Very Slow, Suspected T2 Problem?

Hello, I have an A1990 MacBook that was running very slowly. I'm not sure why I jumped to this, but I went straight to doing a DFU restore (and tried a revive later). After doing the restore, I got the flashing folder icon, this is expected behavior. When I try to enter Internet Recovery, the globe spins erratically for a second before allowing me to select a network. When I move the cursor, it is very laggy, but the keyboard is perfectly responsive. It takes over an hour to reach the recovery OS after connecting to WiFi. I have checked all the SMC power rails and found nothing wrong, I'm not sure what I'm missing.

Extra details:

- Using Apple Configurator 2 on an M1 Mac Mini with an Appl Thunderbolt 5 cable
- Using an Apple 140W power brick
- The restore starts, gets to about 40%, then hangs for a couple minutes. In this time, the MacBook gets the reset signal and boots to a screen with the logo and a full progress bar. It sits here for a couple seconds before turning back off. Eventually I see the Apple Controller appear to refresh in AC2 while the restore is ongoing. Shortly after this, the "installing system" box disappears with no success or fail message and the icon changes from the DFU dotted box to a lock. Additionally, a yellow warning appears next to Apple Controller, clicking it states essentially "this device is not booted, please use the restore option". If I check "get info", it says it is booted. Like I said above, I don't know what I'm dealing with here. Any help would be appreciated!

First of all, welcome to the forum!

Did you have a good battery connected?
You should also test known good trackpad board/flex.
The fan went to max speed, before doing DFU?

Hi, thanks for the welcome.

I have fully charged the battery, but I don't have a new one to test with.
I can try another touchpad+cable, I'll get back to you on that
The fans never maxed out, no. They spin slowly while the MacBook is on which is about what I expect

Quick update: I haven't tried anything new with hardware yet, but it failed to boot into Internet Recovery. I tried again to see if I could potentially install MacOS (however slow it'd be) and run commands to check things, but after multiple hours of waiting it errored out with -2003F.

This problem can be solved sometime using ethernet connection, or shared wifi internet from a mobile phone.

Can you run embedded diagnostic?