Firstly, clean boot system to exclude the influence of third-party software.
Next, run sfc /scannow to repair broken system files.
Check your disk state by some disk testing tool such as HD tune, loading issue might be related to disk.
Then, download the software "Process Monitor": https://learn.microsoft.com/en-us/sysinternals/downloads/procmon
Start "Process Monitor": There you will find the file on which dllhost.exe attempts to get access over and over again.
When you have found your file, remove the file from your computer.
There is a video tell you how to operate.
How to fix COM Surrogate high CPU usage in Windows 10
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