Is your theory that any kind of testing or isolation in groups who have low/few symptoms (children), is causing the rise in cases because not enough children are catching it quickly enough and spreading quickly enough?
No, it causes persistent high levels of detected cases, imagine two areas one which detects 20% of cases and one which detects 50% of cases, and detecting a case is completely successful in stopping another case from then. 1000 in each group at the start. We'll seed each group with 5 cases and an R of 2.5 with a period of one week.
The area that only catches 20% of people has almost everyone infected in 10 cycles and topping out at around 40 cases and just three "weeks" has a rate over 10/1000 , the area that catches 50% of cases though takes double the time to infect everyone and 12 weeks of that is over 10/1000.
Both places end up just as infected, but the lower detection rate makes that area appear a lot better.
Now if the serious complicates rate in both was high, we'd know that there was a huge discrepancy the low detection area would have had the hospitals overwhelmed, but if the populations have very low rates of serious health risks (due to vaccine protection, or the spread being only in very low risk age groups such as students, children etc.) then the more rapid spread in the first area would not be noticed.
Now I don't remotely think the difference in detection rates are that large (or the R rate, or the complete reduction if you detect a case) but it does illustrate how detection rates don't have to line up with actual rates.