Latest AMD miniPCs APUs have DDR5 memory (up to 96GB). Don't know about the channels.

But this APU hack might work:

https://blog.machinezoo.com/Running_Ollama_on_AMD_iGPU https://github.com/ollama/ollama/pull/6282

Linux since 6.1 made some changes to allocate the memory to the GPU from userspace, but it seems the GTT method has degrated performance even more.