HELP!!!?? "PowerPC Applications are No Longer Supported"

I need MAJOR help. Either a critical bit of hardware was unintentionally deleted, or somehow my iMac updated itself into obsolescence. Wouldn't be the first time on the latter... I am still mourning the loss of my old MacBook Air to a Catalina update a few months back that turned it vegetal. ANYWAY I sure am hoping that I can reverse engineer my current problem... Thanks for your help.

What's wrong?

Nothing works.

This is a 24in. iMac with OS X El Capitan

It is telling me I cannot open any of the apps on the iMac because PowerPC is no longer supported.

I woke up today and sat down to pick up where I left off last night, and I am unable to do ANYTHING. I watched in front of my eyes as my Chrome widget disappeared from my tool bar with the alert that my system no longer supports it.

An attempt to open Safari to re-download Chrome yielded the discovery that I am also unable to perform a basic Search on the iMac at all. (See screen shots, attached.)

I then went to open Mail and discovered that ALL of the iMac's applications in Finder are now labeled as "Name.app" and their thumbnail logos no longer display.

What the h*ll happened to my computer?!

I am beside myself. I literally can't even "dial out" by opening a webpage or an email and contacting Apple from my computer. I'm typing this on my phone...

Like I said, I already lost a MacBook Air to an unsupported Catalina update this Winter. I have no idea if this iMac disaster is a symptom of the same issue with Apple serving unsupported updates to old devices that they no longer even support via tech support, but I am beside myself and need major help to reverse engineer my way out of this nonsense.

All I can think to do is somehow locate the missing PowerPC app and hard-xfer it back to my computer via my phone... Because I literally can't open a browser or receive email on my iMac now.

Please, please can anyone out there help me?