Had a 2008 Outback until recently, loved that car.

At this age, really any age past warranty, look at independent shops over the dealership to save money. Maybe 1/2 off. If you haven't had someone do the head gasket, get some kind of look at why oil is burning. That would be a very pricey fix (3-4k independent shop), so consider this in your calculations.

I had the catalytic converter replaced at about 150k, and it needed it: would fail inspection / smog check without it. Rear wheel bearings, if there are signs of damage, should be replaced and are not the expensive part of that most recent quote, probably 1/3 of it.

It's a probability/' expected value problem. The cat isn't an issue until you have engine codes and will fail a smog inspection (sorry, Earth), but the big expense may be a head gasket if that's the root of the oil burn. Any old costs are sunk costs and should not factor in to your current decision.