I don't see how GOMAXPROCS alone can help here though. You would have to use Topology Manager (single-node policy) to avoid cross-NUMA allocations. This is in addition to other managers - Memory and CPU Manager.
CPU Pinning (via CPU Manager's Static Policy) will also be required to ensure your processes don't just get a CFS quota/share but are actually pinned onto specific CPU cores.
I checked out the listings on idlefish and I was able to find some with 350 CNY (~48 USD). That seems like a really really good deal. Please, do keep us updated with your findings after you've purchased it.
CPU Pinning (via CPU Manager's Static Policy) will also be required to ensure your processes don't just get a CFS quota/share but are actually pinned onto specific CPU cores.