Long story short, get Atlas if you don't expect to cross 1.5L frequently and Substantially.
You can also use the following prompt on ChatGPT. Please modify the figures considering your spending habits/capacity.
"I have two cards. One is Axis Magnus and Other is Axis Atlas. Magnus gives 12 Edge Rewards for every 200 spend. Whereas Atlas gives 2Edge Miles for every 100 spend. Axis magnus points transfer at 5:2 ratio while the Edge miles transfer at 1:2 ratio.
Axis magnus has a feature where the Edge Rewards are 35 per 200 Rs spent for monthly spends above 1.5L upto the credit limit. I have credit limit of 10Lakhs.
Atlas has milestone benefits of 2500 Edge Miles on spending 7.5L and additional 5000 Edge Miles for 15L spends in a card anniversary year.
Now give me comparison for both card for Annual spend of 5L, 10L, 15L, 20L. For 15L and 20L spends consider 3 months where spends are approximately 3L"