Death Rattle and when erg blocked car almost dies.

Work with what you have.

I drove a civic for a while that burned a quart every 250 miles. I just got gas and refilled the oil every morning and kept chugging along. I put 25,000 miles on it in one summer actually and it did fine. I did have to check the spark plugs here and there as they would coke up and cause a misfire. So I would keep 4 extras and swap them out to sand blast the ones that came out here and there to clean them up and have them ready to go back in and kept the process going. Cat threw a p0420 so we did a right angle spark plug antifouler on it and it got the light to go off permanently. That was it. Sold it to the next guy and he kept going.
For your prius since you did all that unfortunately you may have scratched the cylinder walls and increased oil consumption. Itty bitty gouges can cause big oil consumption.
At this point I would try a piston soak and see if you can decrease the oil consumption a bit to make it more tolerable. May want to disable the egr system now as it will be perpetually clogged with oil sludge and carbon from here on out much much quicker than normal.

Burning 3.9qts every 1000 miles | PriusChat
Gen 3 Motor Issues - Piston Soak - Blowby Pressure | Page 2 | PriusChat
"EGR DELETE" Instructions | PriusChat