MacBook Air System Data 70GB causing issues - can I clear?

Reducing System/Volume/Data is a common question. 

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How to free up ‘System Data’ and other storage on your Mac from a fellow colleague  

There are  two effective ways to remedy this issue:

1. Quick Fix Actions:

   For Apple Silicon computers, use Disk Utility to erase a Mac.

 For Apple Intel computers, use Disk Utility to erase an Intel-based Mac, then reinstall macOS.

Always make a Time Machine backup before proceeding.

Migrate only the user account, not the entire system.

 Reinstall only the necessary applications from the Apple App Store or directly from the developers.

2 - Generally

When the user discovers this issue, it’s likely because the computer’s internal drive capacity is small, such as 256 GB .

Note - On Apple Silicon computers and newer Apple computers, the SSD drive and the Unified RAM are Soldered to the Logicboard and can not be upgraded

Unfortunately, the user’s storage needs may have increased since the computer was purchased. To future-proof the computer, consider spending extra money upfront on a larger drive capacity and adding more unified RAM. 

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Suggest you get an External SSD Drive with maybe 1 TB Capacity

Dedicated this drive Only for 1 purpose

Start moving your Pictures, Music, Videos and any other large files you have control over, Off of the Internal Drive and Onto the External Drive