This is indeed a very good point. I made the test on my windows machine with unity 2019lts. I will make another test with 2021.2 later on. Thanks for bringing that up!
//EDIT:
made a test - windows 10, 10th gen i9:
2019: Script compilation time:1.772s
2020: Script compilation time:1.867s
2021: Script compilation time:3.235s
this THIS puts the m1 into a new light for me, thanks for bringing that up!
started a new thread: https://discussions.unity.com/t/844260