It is not. According to [1] M1 GPU can run "up to 25000 threads".
Comparing raw numbers between vendors is always tricky, but it looks like Apple's "cores" are more like Nvidia's 'Streaming Multiprocessors' (SM's), of which their cards have between 14 and 100.
M1 seems to perform similar to their older, mid-end desktop cards (1050 Ti has 6 SM's and M1 matches it in benchmarks).
Comparing raw numbers between vendors is always tricky, but it looks like Apple's "cores" are more like Nvidia's 'Streaming Multiprocessors' (SM's), of which their cards have between 14 and 100. M1 seems to perform similar to their older, mid-end desktop cards (1050 Ti has 6 SM's and M1 matches it in benchmarks).
[1] https://www.apple.com/newsroom/2020/11/apple-unleashes-m1/