....I have to admit that I personally do not congratulate every shot, when they fundamentally look like many other.s...photo fatigue? ...
I do not believe there is photo fatigue per sé, but if many shots are similar, there is a lack of originality.
Repetition is useful to build technical skill, but it is variation and novelty that generates interest.
The most likely explanation for a reduced number of comments, is reduced interest, because of a lack of variation and novelty.
This can be fixed, if there is interest in fixing it.