safari crashing constantly in Big Sur

      Download EtreCheck: https://etrecheck.com/  and post the report here.

      Click, “Free Download” button and then  “Click to download” button,

      open Downloads folder, click on it to open, and then select ”Open”.

      “Choose a problem” from the popup menu box, and then “Start EtreCheck” in the dialog.

      Click “Share Report” button in the toolbar and select “Copy report”.

      Click the “Page” button in the toolbar at the bottom of this page and paste it when you reply.

      Note: This is a diagnostic test. 

From the EtreCheck report:

Minor Issues:

These issues do not need immediate attention but they may indicate future problems or opportunities for improvement.

No Time Machine backup - Time Machine backup not found.

Configuration profiles found - This computer may have configuration profiles installed. These are sometimes used by adware and malware.

Apps crashing - There have been numerous app crashes.

Clean up - There are orphan files that could be removed.

Unsigned files - There are unsigned software files installed. Apple has said that unsigned software will not run by default in a future version of the operating system.

System modifications - There are a large number of system modifications running in the background.

Kernel extensions present - This computer has kernel extensions that may not work in the future.

Sharing enabled - This computer has sharing services enabled that could be a security risk.

Remove the Configuration Profile, you have not installed knowingly.

https://support.apple.com/guide/mac-help/configuration-profiles-standardize-settings-mh35561/mac

Temporarily disable TrendMicro and test, even though it is found in the legitimate list and probably OK.

safari crashing constantly in Big Sur