VW Polo 6R 1.6 TDI: Persistent Power Loss After EGR Valve Replacement

Hello everyone! I come to you because I have a small problem with my POLO 6R 1.6 TDI. I had a gradual loss of power a few weeks ago, we checked with the mechanic and he diagnosed that the EGR valve was broken. We therefore changed the valve but on the other hand, I feel that the car has not regained all its power and while doing research on the internet, I found an article on engine carbon. So, I wonder if this could be the cause since everything concerning the EGR valve has been adjusted.
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If the EGR valve is new and you still suspect that it is not working properly, you should check whether the elements controlling it are working properly, namely whether the actuators in the valve receive the correct signals from the engine ECU. Regarding carbon in the engine, I assume that you are talking about carbon deposits that accumulate on engine components. It is a fact that if, for example, the engine intake is dirty with a mixture of oil and carbon dioxide, the car may have less power.

And the most important question is whether the EGR valve was replaced with an original one or a replacement one? Because it often happens that the problem with these replacements is that after replacement they no longer work, so replace them only with the original ones. I did it at home in a Ford C-Max 1.6.