Get a complete and current backup, maybe get another backup, boot from Recovery or from a bootable installer, wipe the disk and reinstall macOS, and migrate in from one of your backups.
It's possible this is also a failing storage device or other failing hardware, as that routinely shows up with corruptions and crashes and performance problems and related. Getting the backup is what you'll want to do for this case, too.
The Diagnostics and the Hardware Tests might—but don't always—show latent hardware problems.
If you've ladled on any add-on security tools or any add-on cleaning tools or any add-on performance-optimizing tools, remove those per the vendors' instructions, reboot, and try again.
It's also possible that your login environment is somehow corrupted. Create a second login, and see if the apps launch better there.