According to Apple Insider, it has confirmed none of the machines will support eGPUs.
As Paul Gerhardt mentioned in a tweet, tech spec pages for the new machines reveal that none of them are compatible with external GPUs that connect via Thunderbolt. It touted impressive performance marks for the new machines and promised excellent battery life, however they won’t come without any compromises. Today Apple showed off the first Macs powered by its new M1 CPU, with a new Mac mini, MacBook Air and 13-inch MacBook Pro.