Sentence examples for may but from inspiring English sources

The phrase "may but" is not used in standard written English, and is considered incorrect.
If you are looking for a phrase that means "although" or "even if," then you can use alternative phrases such as "although," "even if," or "despite." For example: Although she was nervous, she performed the presentation well. OR Even if it's raining, we will still go for a walk. OR Despite his fear of heights, he went on the rollercoaster.