Mac Mini Server Mid 2010 (Macmini 4,1) - OCLP issues, help please

Hi! I have been struggling with installing Big Sur (or any other supported OS to be honest) to my gf's 2010 Mac Mini. She needs to install InCopy 2024 for a job and we can't afford a new Mmac yet.

Backstory:

• I replaced 1 of the 2 HDDs with a compatible Kingston SSD, 480 GB.

-I installed the latest supported version, MacOS High Sierra, and updated everything to the latest version. I even managed to install High Sierra to both drives separately to have an OS to build the OpenCore LP drives when installations fail.

• I downloaded OCLP 1.5.0, and used it to download the latest version of Big Sur. I created an installation drive and proceeded with the installation following their guide.

The first few attempts resulted in "proper" installation procedures but the first boot would get stuck on the loading bar.

I eventually enabled debugging in the OCLP drive, and found that it was getting stuck due to a Kernel Panic error:

Sorry for the picture, High Sierra is appearenlty not supported by EFIMOUNT.

I then attempted to install High Sierra again, after seeing a post recommending that the OCLP installation be done on top of the latest version of the supported OS.

I attempted the fix described in stuck-on-boot-after-root-patching. My terminal rejected the xargs command, but I was able to list and delete every non-HighPoint or SoftRAID file.

That failed similarly. I couldn't boot even to an unpatched version.

The second series of attempts involved trying the following combinations and outcomes, some on the HDD, some on the SDD, for a change:

1. OCLP 1.3.0 + Big Sur -> Stuck on first boot
2. OCLP 1.5.0 + Monterrey -> Kernel Panic (see ss)
3. OCLP 1.0.1 + Monterrey -> Loading bar stuck again
4. OCLP 1.4.2 + Sonoma -> Installer couldn't see my drives
5. OCLP 1.5.0 + Sonoma -> Installer completes, gets loading bar stuck at the end.

I'm currently on day 4 of attempting to do something different that gets me through:

I'm trying OCLP 1.5.0 + Big Sur with debugging, as I'm typing this. If you need any logs or screenshots or information to point in a better direction, just say so, I'm starting to feel desperate at this point.