Even if it's just 1-2 members in the year, I would consider that normal turnover regarding their operations, as they are likely to introduce high-quality talent within the following months, if we're going by the last few years as an example (Advent, Tempus v1 + v2, etc) - and if not, the already existing talent have more than proven their worth content-wise to help ease the pain
Nijisanji, on the other hand, may not be able to accelerate enough to replace everyone lost without yielding a net negative
...If Fubuki graduates, however, then all bets are off.