The most important reason for the "dimming" of the comet C/2023 A3  is the change in the phase angle. The comet seems to "turn away" from observers, therefore it seems that the brilliance of the comet begins to fall after the confrontation and this is normal - it will not affect the brilliance of the comet in October. 
This argument means that in September-October of this year, this comet can safely reach exactly 1.00 magnitude, which means this comet will be comparable and even more beautiful than comet C/2020 F3 NEOWICE.

Can't wait to witness the beauty of comet C/2023 A3 in September-October! 🌠 