Normally drone races are organised by clubs and associations. In such cases, they may have received operational authorisations from the IAA in accordance with Article 16 of Regulation (EU) 2019/947, which also covers the organisation of such events. If, instead, you want to conduct a race that is not within a club or association and with no spectators (in this context meaning uninvolved persons, see the definition above) present, you will fall under the ‘open’ category, and you can operate under subcategory A3.
The Regulation allows you to fly without keeping direct eye contact with the drone, provided you have a person next to you, a UA observer, keeping direct visual contact with the drone, scanning the airspace to make sure that you do not endanger other parties such as aircraft, buildings, or persons. The unmanned aircraft observer must be located alongside you so they can immediately communicate with.