Timing belt and water pump for an extra grand on a Subaru is a bargain. I had to replace them a couple of years ago on someone's car, and it's a PITA.

Watch for corroded head gaskets. Especially in WI. That's one problem with Subaru flat cylinders: they are right down there in the salt spray on a horizontal surface where the drips just hang there and eat away (like a political rally). Newer ones are a little better (stainless instead of copper). I'm surprised the mechanic didn't recommend those when he did the timing belt, but he probably couldn't get the bolts out of the covers....

Oh, and the Subaru engine isn't meant to be rebuilt. It's meant to be replaced as a unit. Most newer cars are that way: they are 'grown' in a factory like an iPhone. It's a one-way process. Sure, it can be done, but it's only really sensible to do a thousand at a time in a factory rebuilder's shop (unless you have a F-I-L with a lot of tools and free labor ;).

"Right to Repair" has to start with "possibility of repair".

Complexity and accountants enshittify everything.

It's not usually the engineer per se that you need to talk to: it's the IRS and the complex tax code that puts accountants in charge of everything. That's why all those start-up geniuses have no plan beyond selling out to a bigger fish who can afford the tax lawyers, lobbyists and accountants to overpower common sense (democracy).

I just bought a replacement truck this year. It has 280K miles. The old truck has 240K, but Wisconsin and Iowa have most of the body parts broadly distributed along salt-soaked roads.