I have been doing some basic calisthenics for about a year now. Mainly just doing push ups, inverted rows, squats (I mix the squats with lunges sometimes) 3 times per week for 3 sets each, every set to failure except for the leg exercises. Sometimes I throw in some skill work, like frogstand or some gym ring shenanigans. I am a 25 year old male, quite heavy at 98kg, so when I started I was doing mainly easier variations like incline push ups etc.
I have a question regarding my perceived progress, during the last couple months especially. When it comes to my muscle size, I have noticed significant changes when it comes to size of my arms, quads and chest. I am also quite happy with my strenth gains; when doing strength skills like back bridges or handstand walks on the wall for example I notice them to be significantly easier than when starting out, even though I don't really train for them.
But I have noticed that the number of reps I do does not nearly increase as fast as I though they would. About 3-4 months ago I was doing 3x6 push ups per workout. Currently I am doing 3x13 and to me that does not seem like a large improvement for multiple months of consistent work, especially because the increase in reps seems to slow down. My short term goal was being able to do 3 sets of 30, but that seems like it's going to take forever. Most people active in calisthenics I have talked to seemed to imply that you outgrow push ups after a month or so and need to switch to a harder variation like diamond push ups quite soon. My experience doesn't reflect that.
Is incresing your rep numbers supposed to take that long or is there something I am doing wrong with my approach? I have never really taken a week off my training, so I was thinking maybe not doing deload weeks could be a mistake and slow down progress? But if that's the problem then wouldn't my size and strength gains be hindered too?