You know, i saw those results last week, but i just can't feel optimistic about. Good junior athletes come and go (at least here) all the time, but only a select few make the transition to a good senior level. It's not only in athletics, but with all sports, there is just something broken in our system, that can't push juniors into the top of the senior level.
Whether it's the financial situation, the coaching methods, the training preparations, the athletes desire and motivation, there is always something, that prevents the majority of juniors breaking through. And i'm sure this could be said for any country.
Will see, what will happen with Mitkova. The same was being said about Alexandra Nacheva. World Champion, Youth Olympic Champion in 2018, bunch of other medals, big talent aaaand her PB is still from that 2018. 4 years after that, she hasn't shown any progress, better jumps, she is basically on the same junior level as she was, when 16-17.
Just another example from the past 10 days. Apparently we won some fancy juniors women's tennis team cup and people were gushing what a prosperous group of girls we have, everyone is the best in their age group yada-yada (tennis has become a rising sport between kids, because of Grigor Dimitrov). I can bet a good amount, that those girls won't even reach the top 100 in the WTA in years time...