Decision time, keep, sell, or possible junk - 2005 Prius 173K millage

Bought it new, it turned 20 in February seemed to be running fine, but then things started breaking.

$4500 To pass inspection mostly due to extremely corroded rear suspension. Decided to pay for the fixes, because cars are so expensive these days. The shop seemed to think the car was otherwise in good shape for it's age.

Two weeks ago, check engine light comes on. Stuck engine coolant valve. Fortunately, stuck in the open position, so the car is driveable. To fix it would be $1500. Also, they noticed the front suspension has started to leak. That would be another $1500, but it could be a year before it's a issue. Or a couple of months.

Also, noticed that the MPG for the first time in warm weather has dropped before 40 MPG.

Trying to avoid the, Sunk Cost Fallacy, and not throw more money into the pit. Options? What made you decided to call it quits on your beloved Prius?

Also, would anyone want to buy a car with so many potential issues or maybe it's junk yard time.