I have two questions about using the present perfect and past simple. To ask my questions I will use the cover letter I wrote (an abridged version).
I have been working for two years at X. During this period, I have analyzed A. In addition, I have deepened my knowledge of B. Finally, I have developed and manteined C and have created D.
At the time of writing I am still working in this company.
To decide whether to use the present perfect or the past simple, the criterion I used is: is it an activity that I continue to carry out (or that I could resume in the future) or that has ended definitively?
I have analyzed... because it is an activity that I do often.
I have deepened... because the learning process continues over time.
I have developed... because C may still require changes or additions in the future.
Are my choices right so far?
If the creation of D was complete, should I use the past simple, i.e. just created? Or can I still adjust to the rest of the text and use the present perfect even if the creation is finished (as I wrote it, it is as if I am saying that creation is not complete)?