Dear Seth Kessler,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
As per your description, please don’t worry, we can work together to narrow down and resolve the situation.
Based on my test result, when I tried to use ‘column-width’ below JSON to change the width and it work for me
{
“$schema”: “https://developer.microsoft.com/json-schemas/sp/column-formatting.schema.json”,
“elmType”: “div”,
“txtContent”: “@currentField”,
“style”: {
“width”: “100%”,
“white-space”: “nowrap”
}
}
For reference: Use column formatting to customize SharePoint
As the column will auto resized based on CSS code. Add an Editor Web Part in your SharePoint page and modify the core CSS. You can add the script editor web part and add the code below to the script editor web part.
<style type='text/css'>
.ms-vh-div[DisplayName='<ColumnName>']
{
width:250px;
}
</style>
For your reference similar thread:
Increase column width in a list view web part
How to increase the width of a SharePoint Online List column in a List WebPart
Your understanding and patience will be highly appreciated. I hope that you are keeping safe and well!
Sincerely,
Waqas Muhammad
***Note: In the event that you're unable to reply to this thread, please ensure that your Email address is verified in the Community Website by clicking on Your Account Name > "My Profile" > "Edit Profile" > Add your Email Address > tick "Receive email notifications" checkbox > click on "Save".***