According to your opinion and experience, what is the best, published an article each year or participate in 10 seminars/conferences each year, including 5 with proceedings or proceedings published?
You can publish an article per year as well as participate in conferences. I always view conference presentations as opportunities for getting feedback on the paper I presented that might help me re-write or revise the paper before submitting it to a journal. In USA research universities, conference presentations don't count for much toward getting tenure or being promoted or even getting a salary increase. Publications are the means to achieve tenure, promotion and salary increase. Trite but true: publish or perish. Best wishes
For most fields (computer sciences being a notable exception), journal papers are far more important than conferences. However, not all journals are equal, nor are all conferences.
Journal publications, in the right journals, have a far wider reach than conference presentations. They are essential for building standing in your field.
In many fields conferences are not primarily meant for dissemination of results, but indeed for getting feedback on work in progress, and especially for building an international academic network.
For a successful career in academia, you will likely need both standing in your field and an academic network.
Hence, instead of going to many conferences (and 10 a year, 5 of which with proceedings is really a lot), I would select one or two specific annual or bi-annual conferences, and try to go every time. That is best to get involved with that academic community.
In conclusion, try to regularly publish in a good journal, and frequent one or two conference series.