Reduce mp4 file size in AE2022

I'm having issues exporting a video file. The original file is a 64MB .mp4 file, from which I then deleted some footage. However, on export, the file size (H.264, video bitrate target = 2, max = 5, audio bitrate is 320) increases to 545MB. 

It's been awhile since I've done video editing, so I'm sure there's something I'm missing. Any idea why this is happening?