Errors in WDS/MDT deployment for two specific Lenovo models

Question

My company is a Lenovo shop and we stood up a WDS server some time ago that boots computers into MDT to deploy images. We've done all sorts of models, from T480s to T490s, T14s, P51, P52, P53, without a single issue. I never did much with drivers in the boot image because it always just seemed to work. Until, that is, we got some new T14 generation 2 and P15 generation 2 models. No matter what I do, they will not successfully boot into MDT.

What happens is we PXE boot these new model machines, they contact the PDX server, load the boot image, I see the background image we set in MDT, and then we immediately get this image, or sometimes, it displays the prompt to start the deployment wizard, and THEN after clicking the start button it displays this error.

On the P15 gen2:

A connection to the deployment share (path) could not be made. The following networking device did not have a driver installed: PCI\VEN_8086&DEV_15F3&SUBSYS_22D817AA&REV_03.

On the T14 gen2:

A connection to the deployment share (path) could not be made. The following networking device did not have a driver installed: PCI\VEN_8086&DEV_15F3&SUBSYS_22D817AA&REV_20.

Once and only once, a T14gen2 went all the way through the deployment task sequence, booted into Windows 10, and THEN displayed the error.

Some googling led me to this page, where I found that the T14gen2 and P15gen2 have specific WinPE 10 driver packs: https://support.lenovo.com/us/en/solutions/ht074984-microsoft-system-center-configuration-manager-sccm-and-microsoft-deployment-toolkit-mdt-package-index

Ok, great. Problem solved. So I downloaded and extracted each package, created a folder in my Out-of-Box driver packs, imported the drivers into there, made a selection profile for that folder, and configured WinPE to grab drivers from there in the Deployment Share properties, then imported that boot image into WinPE.

Then I PXE booted each model and got the same behavior. I'm a little stuck, and wondering if anyone here has run into this before or has any clues on where to go.

Also, originally, I just left the WinPE drivers on 'All,' imported all of the P15g2 and T14g2 drivers into Out-of-Box drivers, and just let the boot image grab what it needed. That broke everything. Computers would boot from the image and then display a message saying that Windows couldn't boot because iaStorAfs.sys couldn't be found. I had to rebuild the entire MDT environment to recover from that.

So right now, just the WinPE drivers for the T14g2 and the P15g2 are being injected into the image, as well as the drivers for the USB-C gen2 dock (https://download.lenovo.com/km/media/attachment/USBCG2.zip). Every other Lenovo model still boots into MDT no problem, and the two models I loaded drivers for don't.

Any insight appreciated! This has been driving me nuts for a while.