W10 2004 and 20H2 are one in the same for the update problem, both the Feb and March update KILL performance. Get rid of KB5000802 and then KB4601319 that will most likely take it’s place. Last security update you want to see is KB4598242, aka January 2021.
You must also follow up with blocking the now March update using Windows Update Show Hide application you can download from MajorGeeks.com I’m unable to find it available from Microsoft anymore.