X3 problems

I have a 2019 BMW X3 s30i with a little under 98k miles on it. The past year I’ve noticed the car has been burning oil more frequently than usual. I have to fill it with oil about once in between oil changes and discussed it with my mechanic I was concerned months ago, he said it could be weather conditions, how often I’m driving, etc but that there were no visible oil leaks, no engine light on and to just let him know if I notice anything else. Well about two weeks ago I noticed small puffs of white smoke on start up coming out of the tailpipe and quickly went away. He had told me that may just be regular condensation build up and keep watching if anything changes.

Well this morning a large cloud of white smoke came out of the pipe and it almost seems like it’s struggling to start (which could be the battery since it’s 3 and a half years old plus live in AZ) so I contacted him and without even looking at it he said it must be the turbo needs to be replaced and that it can’t be much else.

That is an extremely costly repair from what he’s quoting 3500-5k on a replacement. I have already replaced the engine oil housing, radiator components, engine mounts, turbo return hose in the past 3 years. This car seems to just require very expensive repairs all the time, it’s never small.

Do I bother going to a mechanic and physically have them inspect it to see exactly what it is? Could it be anything other than the turbo? I did not want to trade in my car until it’s fully paid off in a year and now I’m stuck on whether I really need to before my problems just get even worse on this money pit.