It sounds like you're looking for a version of VMware ESXi 7.0 (vSphere Hypervisor) — likely a bootable ISO that can run from a USB drive without a full install.
autoPartitionOSDataSize=8192 boot option. If that fails, use an M.2 SATA SSD in an external enclosure (ESXi sees it as a standard SATA drive, not USB).Once you have created the portable ESXi 7.0, you can boot from it by: esxi 70 download iso portable