The main region for Antimalware Service Executable High Memory is 'Windows Defender'. You have to dissable Windows Defender first to fix this kinds of issues instanty. Here are the simple steps that you can use to fix your issues.
Go to ‘Settings’
Go to 'Update and Security' option 'of your Windows'.
Select the Windows Defender option
Click on ‘Open Windows Defender Security Center.’
Select the ‘Virus and threat protection’ option to turn off the real-time protection of ‘Windows Defender’. If still you have issues then visit here:
https://dev.to/robbinhoo...table-high-cpu-usage-p4n