Projector mount with 2 or 3 screws

Berkeley, CA has a tool library for just this kind of rental. Major home stores have rentals, and there are chains of rental shops like Hertz Rentals.

You'll need a drill, a masonry bit, and a concrete anchor. Your local hardware store can supply the last two. Each anchor will have a specified hole size.

The ceiling is almost certainly not cinderblock. But it could be reinforced concrete, which is a good strong material to anchor to.

4 kg is not very heavy. 2 screws should be no problem, for the weight. 1 cm diameter screws are very strong and would hold 10 times that much weight. Even 4mm to 6mm screws would be plenty enough to hold up 4kg.

Based on the mount that you linked to, you should not need to install it at a 45 degree angle. The tilt section of the mount (as shown in the linked picture) does not rotate, so you probably want to keep the base square/parallel with the screen. The side holes will be enough to secure it.

Is this an exposed beam you are attaching to, or is it a finished ceiling (drywall/sheetrock or plasterboard) with the beam (rafter or joist) above it? If it is a finished ceiling, you also could attach a large board so that it reaches across two beams (such as 15mm to 20mm plywood, perhaps 30cm by 60cm or however far it is between beams), and secure the projector mount to the board. Four screws in the corners of the board to the two beams, and four screws in the corners of the mount to the board, would be very strong and secure.