2010 hard rattle at start and idle

So I recently was trying to diagnose a tire monitor issue, that seems least of my problems. I have a 2010 with 186K had an engine light on\off over past year. When checked it was a p401 Ibelieve. I attempted getting a local diy to clean the erg but never found someone willing or through communication understood what I was looking to do. FF about a week ago I was noticing a rough ide if the hybrid battery was low and I was at a light or slow moving traffic. it would resume normal after I got past 25mph and battery charged up. The car it self maintains power.
Yesterday I was looking online for used priuses as I do to maybe get into something newer and sell this one. This local guy replied he works on priuses and said he could come to me to check out mine. We met he plugged in his scanner and it had a p301 code. The car had a bit of a rough idle start but nothing worse than a few days befoe. He was saying I would need new engine aka rebuilt from lord know where. Full disclusure I am not super mechanically savy. I know just enough about the standards and too disabled to try to work on my own...
Anyway he said I would also need a new cat based on the p401 code causing damage.... He said he would buy mine for 1500.. I was somewhat skeptical but thats just the times we live in...
My reserve over flow tank is where it should be. there was no discoloration. my oil was very low but normal color. had oil change back in may.

After he left I started it back up and the hybrid batt was 2 bars so the rattle was very rough.. I probably will try to get into something else if I can but in the meantime this is the only vehicle I have and well dont have others willing to drive me around to look at potential cars I can get into.

If infact this is the headgasket can I still drive for a bit and try to look at some car lots etc.. I have some appt coming up as well.. or will this just die suddenly while driving potentially.

I think if I get it back out to charge to hybrid and try to avoid stop and go traffic it will or should drive ok for now.

I have been searching countless videos etc mainly youtube where others have same problem and put a can of bars gasket seal in the radiator overflow and that solves there issue for awhile... some say months? this would bide me some time to get into something new.

please be helpful if replying.. I am not a mechanic or DIY wish I was but didnt get that training in a single mother household growing up. I respect those of you who can diy.

 

i appreciate the reply. i agree with the oil. im usually after it but lots going on with health at the moment. i did have sparks replaced a year and half ago. the guy was doing it as a side gig but he seemed to know his stuff.

on a side note this could be an issue or longshot. to save money a local gas chain had all levels of gas on sale july 4th for 1.776 and i already had a half tank so i filled up at pump then went home and had 4 gas cans various sizes and filled them up. one can had old gas so i put that into a seperate container and rinsed it out well. would or could bad gas be an issue. the issue started about a week ago so i have been adding those containers in as i go infact the 2nd time adding i somewhat overfilled. gas didnt poor out of the fill but i could tell i exceeded what a pump would do. the car remained on full pips for 3 weeks and about 160miles then the pips started to go down. i was concerned the gauge was messed up but i believe it ok now

 

no that at this point. I mistakenly had a guy i didnt know who lived fairly close stop by he said oh i can check the spark plugs and that will either eliminate or correct issue. mind you had all 4 replace 1.5yrs ago by someone else who knew there way arounf a prius and the ones he pulled said were not really that bad.
the guy today was rough getting the covering off near where to get to them. grant it there are a ton of screws but.. he broke some clips lost a screw into the frame couldnt find it. He pulled the long injectors? that sit above the plug on cylinder 1 and 2 both looked very clean. he couldnt get the plug out of either 1 or 2 with 3 different socks. he had 5/8 that should have worked unless someone know different. Anyhow there did seem to be alot of gunked oil behind the gasket assebly

it doesnt appesr losing any coolent the reservoir is still 50% and looks fairly pink. I had someone try to pull the spark plugs today. he couldnt get 1 or 2 out using a 5/8 sockets and he had three 5/8 sockets. He was a rough taking stuff apart and back together so we agreed to not see one another. When he pulled cylinders 1 and 2 out they were dry and clean. from the top to top of plug since he couldnt get them out was dry. there seemed to be alot of oil and gunk on the backside of the manifold? where the cylinder and plugs go.

 

thanks i tried to tell him

 

im trying . a lot of fb\ mobile guys talk a good game

 

its hard to because the ones who know more will try to get you to sell them your car so they can flip it. and other need money so they puff