Do I still need to go through security and passport control?
Depends on the exact routing. If you arrive from outside the Schengen area, you will need to go through passport control and customs at your arrival airport. If you leave the Schengen area, you will go through passport control and customs at your departure airport.
Obviously you don't have to collect and recheck bags, since you don't have any.
Whether you have to go through security again, depends on the exact details of your trip, the layout of the airport, the terminals/gates involved and when and how you can get the boarding pass for your second trip.
How much time should I reserve between the flights, so that I can make it to the second flight?
No one knows. Personally my rule of thumb is a minimum of 4 hours and there can be mitigating circumstances to increase or decrease this estimate based on the specifics of the flight details, status, airport, terminal layout, class of service, Known Traveler things (like Global Entry or TSA).
The main problem with self connections is that YOU own all the risk. If you don't make the connection, the second airline will simply consider you a no- show and has every right to cancel your entire ticket. Some are friendly and may work with you, but you can't rely on that. That means, you may be on the hook to buy a new same-day ticket on the spot, which can be very expensive. If there is none available, you may have to buy a next-day ticket and may have pony up for a hotel as well.
For a regular connection, the airline is responsible and will cover all incremental cost. For a self connection that's all on you. Since the factors impacting the timing of a connection are plentiful and complicated, I would only recommend this to experienced travelers, who understand the complexities and are comfortable the managing the risk around it.