How big pagefile do I need

Set the folder options to see the hidden system files
Before running the game,the file size was 2.88GB,when the commit charge went above the limit,the file size became 5.9GB
Process Hacker also showed me how big the file is
When I close the game,the file size became 2.88Gb again

It changes its size and the ssd free space changes too.

Capacity 117GB
Used Space 45.1GB
Free Space 72.6GB

The commit charge is at 14GB currently

Expanding a file does not require writing any data to the file itself. Only the metadata of the file will be updated and that requires little writing. When this is done the data in the expanded part of the file is whatever was in the disk sectors before. This is documented in the developer documentation on MSDN. The pagefile is expanded this way and is fast, and with an SSD, very fast. There are no issues with this, performance or otherwise.

The pagefile will be reduced in size when possible. The ability to do this goes back to at least Vista, possibly earlier. In simple situations like here it normally will be possible but under real world conditions things are not so simple. If there is required data at the end of the pagefile then the pagefile could not be shrunk without data loss. Windows will not rearrange the contents of the pagefile to permit reducing it's size. Doing that could have a serious impact on performance.