How to Enhance Video and Audio in My Video using Final Cut Pro

Hi Guys.

I have this video which was recorded using a Phone Camera in 1080P 60FPS. It has a lot of background noise and so I want to remove the background noise and also somewhat make the colour of the video more colour ful. What do I need to do? Where do I need to go in Final Cut Pro to achieve these two things ? Where should I begin from ?

I just did a little bit of experiment on my own and I imported the video and added it to the timeline and then I went to Modify in FCP and chose Enhance Audio and when I also add Voce isolation and drag it to 100% the resulting file to export is a whopping 550 MB where as the original file is just 50MB why is FCP making this file with this enhancement such a huge file ? How do I ensure that even with the adjustments that Video File Size does not go so high ? While Export I am choosing Apple Devices 1080P option

The original File Information is this

Dimensions: MEO-S AAC, H.264

Colour profile: HD (1-1-1)

Audio channels: Stereo

Where do I start from ?

Also how can I see before and after in my project and compare the original file with the new modified one ?

[Re-Titled by Moderator]