Final Cut Pro constantly hangs, on a brand new high end iMac ordered, with FCP pre-installed.

Please post an EtreCheck report https://etrecheck.com giving the application Full Disk Access in Privacy & Security System Settings. Copy the report and use the Add Text button to paste the result into reply box. 

Normally I would suspect a problem with corrupt media but as you are making new projects this may not be the case OR are you using the same clips for each "new" project?

I assume you have also restarted your Mac in your attempts to troubleshoot.

Stop using Chrome and delete everything in that article.

Yes, I know Safari can be rubbish with certain websites but you can use Brave. I believe it is based on a similar foundation to Chrome but minus its nasty bits.

I use it whenever Safari is playing up.

https://brave.com/

Also avoid CleanMyMac and any other apps claiming to clean or improve the performance of your computer.

Delete the preferences.

Hold down Command and Option as FCP is launched and click the Delete button in the popup window.

Try deleting Chrome and the keystone daemons it uses. https://support.google.com/chrome/answer/95319?co=GENIE.Platform%3DDesktop&hl=en See if that helps.

Whenever the application crashes or you force quit (forced crash) you should trash the settings on relaunch.