Payload creation for Ticket creation

Hello Experts ,
I want create ticket from JIRA REST API . while constructing payload each field have different types and some of the custom fields have type any, array .
/rest/api/3/issue/createmeta/${req.payload.projectKey}/issuetypes/${req.payload.issueTypeId}

I used to get type and allowed values for the ticket fields . in this case for some custom fields there is no allowed values too in this api . how to construct payload in this case ?

I have a info of ,

project_id,
Ticket_type
field_id / field_name

want to construct the payload dynamically including custom fields . can anyone please help . Thanks in advance