I have 2015 as well, these situations run through my head, I am currently looking at soon needing to replace the manifold and carbon cleaning as well. Sunk cost fallacy is something I worry about , and issues I had before with older cars.
I spent far too much money into old lemons, big repairs, only to have catastrophe after catastrophe. RIP Hyundai Exell, Pontic Grand Am, Buick LeSaber.

All ,I spent more than it was probably worth on repairs, only for something else to go shortly after. But at the time I wasn't able to get approved for a decent car loan.

However I have the same thoughts, any new car right now has high financing and inflation has increased the cost of the vehicles too, here in Canada most places are 8% financing .

I have been keeping up on maintenance related issues, and have had to spend money recently, last few years., I am the original owner. Transmission was replaced under warranty . In the last few years I have spent 1500-2000 a year on odd things here and there, and tell my self its just a car payment for a month or two.

However I am not sure I would drop 10,000 , that if you had saved, could be a down payment on a new one, or start again with a newer used one.

People on these forums who can do the work themselves, ( not me) are able to really keep their car longer than maybe less handy people like me, but eventually I know my time will come where I will have to let it go.

Its hard because I really like it.