As far as I can tell, RusFed usually sends one stronger skater and one weaker skater to each event to balance things out, so let's see how the test skating ranks affected the assignments.
Test skates:
(1) Valieva - Clean SP, Clean FS (with quad).
(2) Sinitsyna - Clean SP, Clean FS (with backloaded combos).
(3) Kanysheva - Clean SP, Clean FS (but with shaky landings).
(4) Usacheva - Clean SP, 1 Fall in FS.
(5) Tarakanova - Clean SP, 1 Fall and Missing Jump in FS.
(6) Frolova - Clean SP, 1 Fall and 2 Missing Jumps in FS.
(7) Khromykh - Clean SP, 1 Fall and 2 Missing Jumps in FS (I put her below Frolova because of shaky landings).
(8) Vasilieva - 1 Fall in SP, WD from FS.
(9) Tarusina - Missed Test Skates (injured).
So for assignments, we have:
Courchevel: Valieva + Khromykh. 1+7.
That's one stronger skater and one weaker skater (if we assume strong/weak entirely on test skates, of course).
Lake Placid: (Sinitsyna) + Tarakanova. 2+5.
This event was more of an exception because of how hard it is to get a US visa, so they assigned those with visas to Lake Placid. You can see this from them having only Tarusina as a sub for this event - unlike all the other events, the other skaters simply weren't options for Lake Placid. No visas, after all. But technically speaking, they still did assign one skater from the top half of the list, and one skater from the bottom half of the list (if we delete Tarusina, who didn't compete on the JGP, then Tarakanova's 5th technically does fall in the bottom half, even if she's the highest skater there).
Riga: Usacheva + Khromykh. 4+7.
This one is more questionable. Technically Usacheva's 4th does fall in the top half of the skaters, but she's at the bottom of the top half. But still, it's one skater from the stronger half and one skater from the weaker half.
Chelyabinsk: Valieva + Sinitsyna + Vasilieva. 1+2+8.
If I'm remembering correctly, Sinitsyna's place was originally either Tarusina's or Frolova's. She got subbed in after Lake Placid's mishap. So that would make it 1+8+9, or 1+7+8. One skater from the top half and two from the bottom half. There's really nothing questionable about that if we're going off the results of test skates. Unless the argument is that test skates shouldn't matter and the fed should only be looking at skates from the previous season, then I don't see how anyone (the Davydov skaters) were unfairly screwed over at Chelyabinsk. (Sinitsyna was only there as a sub.)
Gdansk: Tarakanova + Vasilieva. 5+8.
This is the only questionable one. It has two skaters from the bottom half of the list. I think the fed might've just decided to sacrifice both to Alysa Liu after both got bronze medals. Or maybe it was a side effect of all the scrambling after Sinitsyna's visa issues and Kanysheva withdrawing from the JGP right around then. The layout clearly wasn't intended because Vasilieva had to compete back to back. I think Sinitsyna was supposed to be there at first? So that does point towards RusFed deciding to sacrifice Vasilieva for her bronze, because they could've had Sinitsyna or Vasilieva compete back-to-back and they chose Vasilieva. Maybe they weren't expecting her to take silver over Tarakanova here.
Zagreb: Usacheva + Frolova. 4+6.
One skater from the lower top half, one skater from the upper bottom half. I think that makes enough sense. Maybe it isn't ideal in terms of consistency, but it does make sense based on test skates.
Egna: Sinitsyna + Frolova. 2+6.
One from the top half and one from the bottom half. It makes sense. The thing that doesn't make sense according to test skates would be the original assignments (Sinitsyna + Kanysheva, 2+3), but that's explainable because they had to push Sinitsyna to the end because of the visa issues, and Kanysheva to the end because of her medical issues.
So in the end there's really no conspiracy theory that I can see. RusFed just put everything down to test skates. Panova's skaters weren't screwed over by having to go to Lake Placid, they were simply the only ones who could get visas on time. (If this wasn't the case then surely the sub list would've been longer). When Sinitsyna's visa issues popped up they scrambled to give her two new assignments with a good period of time in between. Davydov's skaters weren't treated unfairly, they were given bad assignments because they missed test skates. The conspiracy theories are fun, I guess, but at the end of the day, if you look at what happened at test skates then none of what happened was unreasonable. Unless the argument is that test skates shouldn't hold any weight and that we should only be looking at the previous season's results.