The advent of pollution controls made the computer controls necessary to get good mpg, good performance, good driveability, and reliable too. The late 70’s and cars of the 80’s were full of mechanical things to control pollutants but they were also loaded with numerous vacuum lines, tubes, air pumps, and ran lousy in many cases.
If you want simple get a basic Honda Civic with as few gadgets as possible. Or similar car by the mfg’r of your choice.