Create a wordpress plugin

Hi all, we have a website on wordpress and we continousley post thousands of pages every week for SEO purposes.
But on thre longer run this will cause problems and we have a;ready started to see the negative effect on the site performance.
What we need is to delete thousands of pages on a regular basis.
but those pages won't be categorise by date, name, autheor or any of the avaialbe wordpress filters.
They have to be filtered based on how good or bad they rank on search engines.
We have the statistics and all set on google console and analytics.
We now need a plugin that can detect the low ranking pages (we will provide you with the criteria for that) and delete them automatically.
If you can do this job either by any available tools or build a plugin for it we will really appreicate it.
time frame and budget can be negociated after we recieved your porposals.
Happy coding.