If you have access to the backend then this may do it (would need building out to make usefull), it is only local reads I think:

lemmy=# select count(*) as read ,post_id from post_read group by post_id order by read desc; read | post_id ------+--------- 6 | 8910 4 | 6262 3 | 7774 3 | 4072

No