2016 Mini copper exhaust smoke. No one can figure out what the issue is

I’ve had my mini cooper 2 door for about 4 years now. Back around October I had an issue of lots of smoke coming from my exhaust when idling, eventually had a drivetrain issue, and got a refurbished engine put in back in December.

All the issues stopped till now, about a month ago I started getting the smoke again. Itll happen when turning the car on, idling or driving away after idling for a bit.

Taken it to multiple shops including the mini cooper dealership and no one can figure it out. The antifreeze was fine and at mini they thought maybe it was an issue with the turbo. They disconnected the turbo but I’m still having the issue (which they didn’t even reconnect so now I have to figure out how to do that, if anyone can give some advice)

Unsure if it’s relevant but around the same time I had two issues pop up. TPM stopped working and my AC occasionally will just not work and when it’s on Will make the car feel like it’s shifting into different gears for no reason.