Estimate for engine rebuild?

2010 Saab 9-5 with 190k miles. Car has th GM2.8t V6, which is the same block as the 3.6, just slightly differnt bore abd stroke. Recently lost compression on cylinder 4. Used engines are $1500-$2500, all I have seen have 100k+ miles on them.

Trying to evaluate what to do. I have done a bunch of other work to the car, but scrapping it isn't out of the picture.

I realize that the cost of a rebuild will exceed the value of the car, as these aren't worth much, but I like it.

It could just be a head rebuild, but I'm also looking at it as the enginenhas 190k miles, so if inhave to tear into it, try to make it reliable for a long time.

Assuming heads rebuilt, new timing chains, rings and bearings.

Most of the work I can do myself except the machine work.

I haven't rebuilt an engine before. What is a swag for something like this?