Progress is not always linear and constant, sometimes there are periods of stagnation. Maybe that's why.
Or maybe you and I have reached our natural limit, to overcome which it would be necessary to study and work seriously, methodically, consistently and rationally. If you have the time and the will, good luck !
Why can't I progress further, I am stuck at 1000 elo for months now, I feel like I am about to reach 1100 soon, then I start losing all the games and again I am down to 1000. What should I do in order to progress further in chess ?