Mistakenly trashed Premium elements 2020 and photoshop elements.

Ok no one, not even me, asked what exactly do you mean by "Trashed"?

Try restoring preferences to default :

https://helpx.adobe.com/in/photoshop-elements/kb/preference-file-locations-photoshop-elements.html#:~:text=Go%20to%20Edit%20%3E%20Preferences%20(Mac,are%20reset%20to%20default%20settings.

Before restoring to default ,make sure you have backed up necessary files if there is any .

Reference :

https://helpx.adobe.com/in/photoshop-elements/kb/backup-restore-move-catalog-photoshop.html

Reinstall those programs.

You might have to manually delete some of the files that got left on you system to do the reinstall. Not sure Don't know

Put your disc in the drive and reinstall