It seems the ISU have merged the Season Best lists of both 2020 and 2021 seasons. And rightly so. Then Sinitsyna is well within the top 24 (11th). All the skaters in the top 24 two years ago got two GP spots (except for Zagitova, Medvedeva who didn't qualify domestically in Russia, and Vasilieva who switched to pairs). Khromykh was 24th two years ago but falls down to 26th when you merge the two seasons, so that's perhaps why she only got one spot (but she will probably get the host spot).
Frolova is way down below I'm afraid (36th). It's sad, it seems that Frolova is stuck between juniors and seniors and won't qualify to get a spot in either. There is just too many good Russian women. Frolova's only chance now is to get an early Challenger and do well. For Russian girls especially, it is crucial to get into the top 24 of the SB list. But then again, if there is too many Russian girls in the top SB 24, all of them might not get GP spots anyway (like in 2020 when Gubanova and Tarusina got zero spots).