How to rename files using Keywords?

Ideally a custom script would do this in one step.

A multi-step process using existing scripts would be:

1) Use a script to copy keywords to description or title, which is supported by the batch rename metadata field. Scripts below. Info on how to save and install them here:

https://prepression.blogspot.com/2017/11/downloading-and-installing-adobe-scripts.html

2) Rename using the accessible title or description metadata:

3) Use a string substitution regex find/replace to remove the auto numbering that is produced when duplicate files clash with the same name and replace with a sequence number:

// https://forums.adobe.com/thread/1223292
// https://forums.adobe.com/thread/2318450
#target bridge     
if( BridgeTalk.appName == "bridge" ) {    
keysToDescription = MenuElement.create("command", "Keywords To Description", "at the end of Tools");  
    }  
keysToDescription.onSelect = function () {   
var sels = app.document.selections;  
for(var a in sels){  
md =sels[a].synchronousMetadata;   
md.namespace = "http://ns.adobe.com/photoshop/1.0/";   
var Keys =  md.Keywords.toString().replace(/,/g,', ');// Replace a comma with comma space  
md.namespace = "http://purl.org/dc/elements/1.1/";  
md.description ='';  
md.description = Keys;  
    }  
};  

// https://forums.adobe.com/thread/1223292
#target bridge     
if( BridgeTalk.appName == "bridge" ) {    
keysToTitle = MenuElement.create("command", "Keywords To Title", "at the end of Tools");  
    }  
keysToTitle.onSelect = function () {   
var sels = app.document.selections;  
for(var a in sels){  
md =sels[a].synchronousMetadata;   
md.namespace = "http://ns.adobe.com/photoshop/1.0/";   
var Keys =  md.Keywords.toString().replace(/,/g,', ');// Replace a comma with comma space  
md.namespace = "http://purl.org/dc/elements/1.1/";  
md.title ='';  
md.title = Keys;  
    }  
};  

You would have to use a script that reads keywords and renames files accordingly.