It will take some effort to get from Edgar database. For fund manager, it's the CIK number. For equity, it's the CUSIP.
All the Edgar database is here.
Directory listing of full-index/ (sec.gov)
All the fund managers that need to file with SEC are in the Master.idx file and sorted by CIK number. This file contain about 6,000 fund managers. Changes in holding can be tracked by comparing the 13F-HR report by quarter.
Here is the link of all filings by Berkshire Hathaway Inc.
https://www.sec.gov/edgar/browse/?CIK=0001067983
The Q4 2021 13F-HR report for reporting period Q3 2021.
SEC FORM 13-F Information Table
The Q3 2021 13F-HR report for reporting period Q2 2021.
SEC FORM 13-F Information Table
If need to analyze by equity, then it's more complicated. Need to tally up all the 6000 fund managers and the equities are identified by CUSIP and not ticker. The 13F securities report of all the CUSIP is published each quarter.
SEC.gov | Official List of Section 13(f) Securities
The challenging part is to match CUSIP and ticker symbol.
Ticker / CUSIP Securities Filing Information Search
Yahoo Finance has a Holders report by ticker symbol and it will give a good indication if your report match the top 10 holders.
This is not to discourage you and it can be done.