Apple M1-powered Macs can detect eGPUs and 144 Hz displays, but hardware acceleration may only be possbile with a future macOS 11 update
The Apple M1 has proven to be quite a performer, but it's current implementation does have some shortcomings. One of the main cons with MacBooks powered by the M1 SoC is that they lack any support for external GPUs (eGPUs) such as the Blackmagic eGPU. However, it looks like all hope is not lost as a future software update may possibly resolve this issue.
When Apple first announced the transition to ARM during the WWDC keynote back in June, developer docs (via AppleInsider) that detailed about porting Metal apps to Apple Silicon seemed to indicate that the company may drop support for non-Apple GPUs.
Now, French publication Mac4ever reports that M1-powered Macs can see an external Pro Display XDR connected to a Blackmagic eGPU housing a Radeon RX 580 but don't support any hardware acceleration yet. Support for refresh rates greater than 60 Hz also looks to be a possibility.
AppleInsider further tested the same with the Razer Core X and the Sonnet eGFX Beakaway Box. These eGPUs with cards such as the RX 590, Vega 64, and Radeon VII could be identified by macOS 11 but do not actually seem to accelerate the display. Possible reasons for this could be lack of drivers or changes (if any) in how Apple implemented Thunderbolt 3 support in M1-powered Macs.