2011 Prius Head Gasket at 200k miles

My 200k miles 2011 Prius is the best car ice ever owned. I've never had any issues, never. A few weeks ago, i turned it on on the morning and i heard a weird noise coming from the left side. It sounded like something loose and hitting something. I turned it off, then on until it stopped. The check engine came on, then a couple days later it turned off, then again. Finally i took it in to the dealer. They ran a diagnostic and forge code P0303, (i think) they said the head gasket needs to be fixed. They said it was missing some coolant, that cylinder 3 was busted. The quote came at $3700 (only 350 was for parts, the rest labor) They also recommended to replace the pistons, add another $2300. I spoke to a mechanic who worked at Toyota and he suggested to replace the engine because he's seen so many issues begin after this repair. He also told me this generation came with lots of engine problems and that sadly they come after the warranty expires.
Also said these hybrid cars only have about a 200k Mike lifespan or around 10 years. All these fit for me.

Now I'm wondering if i should even try to fix it. I doubt i could get much for it if i tried to sell it, plus i highly doubt i could sell it for now then the first to fix... Uuggghhhh... I'm torn on what to do!!! Fix it? Get a new engine? That might be quicker and easier. But then a new engine with less miles only give 30 day warranty on the head gasket .... How much longer would this car last?? Should i just part with the car and say goodbye??

I appreciate all comments and suggestions. Thank you so much!!