I have purchased a used 204 DSG 66 plate, registered Feb 2017 T6, with 92k miles.
I’ve since done 13k miles in it, so she’s on 105k now. A new EGR was fitted June 23, and as far I can see, that’s all it’s had done. I purchased it Aug 23. It uses around 1L of oil every 2000 miles, by comparison to some on here, that appears to be reasonable.
I currently have a EML for an inlet manifold runner position, a common fault by all accounts. For a vehicle with 100K+ on I think that’s acceptable, something I am not super concerned about as it runs perfectly at the moment. I’ve also repaired a split coolant pipe.
I have had the EGR & adblue mapped out, and a dsg map to improve drivability.
Whether this makes you feel better or not I don’t know, but we’re at 105k with what I would deem acceptable wear and tear when compared to some of the woes other users have experienced here.
A glass half full outlook perhaps, but the wealth of knowledge and various posts on here associated with the 204 can and should help you prepare for the most occurrences. Be it expected faults or reputable companies to solve those faults. For instance, I’m at peace with the fact I may need a new turbo in the not so distance future, but this forum has provided me with the direction to take should it happen, or even worst case, where to go if the engine gives up the ghost.
Finally, for me, reading this forum did provide a level of anxiety I’ve never had when owning another vehicle. Anxiety that was maybe unjust given my experience of ownership thus far. Good luck!