With the rattling and clunking for the engine plus the oil light being on it sounds like either the oil pump failed or it has lost all of the oil in the engine or both. The reduced power and loss of power steering was the engine starting to lock up from the lack of lubricant.
The first thing I would do is check the oil level on the dipstick. However it is very likely already too late to save the engine even if it was only that it is low on oil. Running for even a short time with low or no oil pressure will damage the engine bearings and surfaces of the crankshaft and camshafts so that they would need to be replaced or reground. If one or more of the bearings locked on and spun in the block that alone would make the block unusable and could be related to the clunk you heard.
Testing wise, the easiest first thing would be to drain the oil as you would for an oil change and look at it. I suspect it will look sparkly and have a lot of bearing metal in it. In that event you will most likely need a replacement engine if the rest of the vehicle is in good enough shape to warrant engine replacement.
Friday, March 5th, 2021 AT 8:55 AM