Earlier quoted context omitted.
I can assure you that performance will not come anywhere close to an RX580, much less to a more modern Radeon 5700.
Where do you think it will fall? Do you think these will be compatible with eGPUs?
These fail because Apple is orders of magnitude away from Nvidia and AMD in performance, plus this is a chip with a very limited TDP. I think they will fall a bit slower than current AMD APUs.