Step 1) Exit Puberty

Step 2) Have a real socio-economic incentive to get up at 6am.

Step 3) Stop drinking caffeine after 4pm.

Step 4) Gene Therapy

Step 5) Find out if you snore. If you’re snoring, you’re not going to get enough sleep during the night, which will make you groggy af in the early morning.

Step 6) At 6am, when your alarm clock goes off, it helps if you really, really, really need to pee.

You’re missing one big step and that is consistently keep this routine. For best results you have to keep it going through the weekends as well.
In my experience, you can fudge the weekends by an hour or so and you’ll be fine. But yes, if you’re sleeping till noon on Saturday and Sunday, your circadian rhythm will be fucked on Monday morning.
I don’t have problems getting up early on the weekends at all. I cut out like 4 hours of sleep on the weekends without issues. I think the problem is that on weekdays I have to get up to go to work.