I like leg press. I can do 3x10 @ 500+ lbs in 10 minutes. That is pretty efficient volume. The leg press at my gym is at a steep angle, and the pad at the bottom is horizontal. This allows a lot of hip flexion compared to other leg press machines I have used. TBH, most of them are pretty poorly designed. Remember, to load it up too. If your machine is at 45 degrees, multiply the weight by about 0.7, and remember that you are not lifting your body weight either.
I also do Bulgarian split squats. I hate them though. Did you get that SSB padding fixed? You can do Bulgarian split squats with an SSB in a squat rack, and if you start to tip over you can just grab the rack. I have done them outside of a rack, and tipped over once. Made a lot of noise, so now I do them with safeties and something to grab.
The belt squat is another excellent option if your gym has one.