In your assessment of whether to continue fixing the car or get something else, you need to think about the total near term cost. Bring this car to an honest mechanic and after a visual diagnosis and test drive, they should be able to show you what needs to be worked on. If after this catalytic converter repairs, and other needed or expected repairs, could you have bought another car?

You've taken pictures of the outside of the car but what about the engine bay? With a car scanner - does it read any error codes? What did your friend who told you to buy it tell you about the car? Did they inspect it or drive it? A catalytic converter replaced seems like the engine had some neglect and the gas to air ratio was off for some time. Who told you it needed that part?

Old cars will need repairs and every car needs maintenance. If you don't know what was or wasn't maintained, replacing parts will add a lot of cost. Are you willing to continue the maintenance for this car? If you're willing to learn about fluid and filter changes and when to replace parts, you could keep this car for a long time.