Correct about the constant aspect approach with a glider, and also we carry extra energy with a speed significantly higher than best glide. Typical best glide speed for a modern glider is around 80 kph, aand approach 100 kph, though this will vary according to local conditions. It's a lot easier to land in a field with a glider than with an aircraft minus the use of engine though, airbrakes are a very powerful tool for approach management. Add landing flap to this, and we can touch down with great precision. A few gliders also have a tail parachute, but this is not common. It does shorten a landing run, but requires a lot of skill and judgement to stream if you intend to use it on final approach. We don't usually need to sideslip except in a few vintage types.
The aim is to set up an approach using half airbrake, which allows a reduction of brake if landing short, until back on the glide path, or more brake if landing long. If the glider has landing flaps then one normally sets them on the downwind leg then leaves them alone. Full airbrake in the hold off will shorten the float