It’s my hobby Brother, but I get your point
To be honnest,
If you quote yourself “what could posssibly go wrong” you’re not making the impression that you did this kind of job before. If you have no clue, a lot can go wrong. Debris in the inlet of the engine could cost you your engine block, a blockage in the oil supply or return could instantly cost you the new turbo. Solving a small leak with sealant wil also cost you your new turbo if it comes into the oil tube.
With some basic knowledge a turbo replacement is perfectly doable. If the housing is still good you can buy a turbo core, this is the bearing with both the compressor and turbine already attached. If there’s too kuch play in the acle you probably damaged the housing and you need a complete replacement.
After the replacement you probably have to tune the variable vanes of the turbo to make sure the delivered boost pressure is within spec. Too low and the engine doesn’t reach peak power, too much and you run the ECU into emergency mode and create check engine light’s.
So long story short, with some basic technical knowledge it’s perfectly doable, but the devil is in the details, thinking what can go wrong will probably mean you miss something, just because you don’t know.
After all, you don’t know what you don’t know.