Your turbo is probably just fine.

If the rear seal of the turbo was gone, you would NOT have oil. You'd have smoke. The rear of the turbo is positioned inside the exhaust system so there is no way the rear oil seal can leak oil into the engine compartment. It would spray out as a mist into the a hot exhaust pipe.

Oil on the compression side is normal, but that usually collects in the intercooler or the induction line. There's no exit for the oil to enter the engine compartment.

Assuming the problem is with the turbo, that leaves the downtube, and a 65-cent composite gasket between the turbo housing and the pipe. I've lost one of these before and it's not a hard repair for your tech. They just have to make sure the mating surfaces are clean. No gasket compound should be used, the heat would be too much.

BUT I SUSPECT you've lost a camshaft seal or something. Did you have your timing and serpentine belts replaced on schedule? Did your tech check for leaks at the seals?

Let me know what you find out, but look for causes other than your relatively young turbo.