Is there any inventory report that shows the quantity on hand per lot number per item AS OF ANY DATE selected? I tried to customize most of the reports in Transactions > Inventory but could not find the right field for quantity per lot number per item. Is this really not possible? Should I just create a transaction saved search? The purpose of this is to compare this against our warehouse count for inventory adjustment as of 12/31/21.

@Luis if you are comfortable with SuiteQL you can achieve this using Tim's Suitelet. I have used modified version of this to get a report like you mentioned as we have serialized inventory. https://timdietrich.me/blog/netsuite-inventory-balance-history-suitelet/