Yes. Bodyweight training builds genuine strength and fitness as long as you keep progressing the difficulty. The levers you have are harder variations, more reps, slower tempos, longer ranges of motion, and less stable positions. Adding one or two resistance bands or a single kettlebell widens the options considerably.
Bodyweight training is excellent for pushing, trunk, and single-leg work. It struggles with heavy hinge patterns and vertical pulling unless you have a bar or something to hang from, and it eventually becomes hard to load the legs enough for maximal strength. Muscle responds to mechanical tension and closeness to failure rather than to the equipment, which is why bodyweight work builds muscle well but very heavy strength eventually needs external load. The mechanisms are covered in Hypertrophy and Muscle Growth and Principles of Strength Training.
A set of resistance bands solves the pulling problem and adds hinge options. A single moderate kettlebell adds loaded carries, swings, goblet squats, and presses. Between them you can run a complete strength programme in a small room.
Browse the exercise library if you want ready-made alternatives for each pattern, including bodyweight and band options.