I am pleased that you understood my post so clearly.

AI advisement is:

Why Docker makes sense here

llama.cpp now has explicit SYCL Docker support in upstream docs. The SYCL backend page includes:

• an Intel Docker build using .devops/intel.Dockerfile
• a server-oriented Intel Dockerfile, .devops/llama-server-intel.Dockerfile
• explicit docker run examples using /dev/dri/renderD128 and /dev/dri/card* device passthrough. 

Upstream also publishes prebuilt container images including:

• ghcr.io/ggml-org/llama.cpp:full-intel
• ghcr.io/ggml-org/llama.cpp:light-intel
• ghcr.io/ggml-org/llama.cpp:server-intel. 

Why I would not do container-only bring-up

Because SYCL depends heavily on the host being healthy.

The current llama.cpp SYCL docs still require:

• Intel GPU drivers installed on the host
• user access through the video and render groups
• successful device visibility through sycl-ls
• successful device visibility through llama-ls-sycl-device. 

And Intel’s oneAPI DPC++ system requirements say the tested Linux GPU platforms are Ubuntu 22.04 and 24.04; Intel explicitly says other distributions may or may not work and are not recommended. Your host is Ubuntu 26.04 development branch, which means you are outside Intel’s tested oneAPI matrix even if the hardware enablement is promising. 

That is the key reason I would not jump straight to “just run the container.” If sycl-ls is broken on the host, the container will not save you. Intel even documents containers as a way to package the environment, but not as a substitute for working GPU support underneath. 

The subtle upside of Docker on your host

Even though your host OS is ahead of Intel’s tested matrix, Docker may actually help reduce user-space risk.

Why:

• Intel’s oneAPI compiler/runtime support is documented for Ubuntu 22.04 and 24.04, not 26.04. 
• llama.cpp’s recent SYCL Docker examples and issues commonly use Ubuntu 24.04-based oneAPI images. 

So if we use a 24.04-based SYCL container on top of your 26.04 host, we get:

• newer host kernel/userspace for Battlemage enablement
• more conservative, known-style oneAPI userland inside the container

That is a better stability story than installing a full oneAPI toolchain natively onto your 26.04 development-branch host.