New iMac with only 8 GB and 256 GB SSD - no upgrade possible.
The market price difference between 8 GB and 16 GB is only 30$ and
also about 30$ is more expensive 512 SSD ...
Look at benchmarks:
https://browser.geekbench.com/processor-benchmarks
Where is M1 chip ? M1 cannot compete in any way with Intel or AMD.
Yes Apple leaves the Intel market but now doesn't offer even similar performance.
ARM CPUs increases performance max 20 % year to year...
So for about 15 years Mxxx chip will be as good as top intel or AMD.