Just because this would be easier for them to have official backdoors doesn't mean they can't ever do anything given enough interest and funding behind it.
>eventually blaming "Russia" for every attack based on trivial IP geolocation
There's plenty of political reasons to state that (even if they were to know otherwise) and if they actually do have more accurate information on a different entity it could avoid showing their hand if they just attribute it incorrectly.
>The reality is that the FBI can't beat maths and has no leverage over services from foreign companies. i.e, a Russian VPN on a clean VM is probably enough to skirt the whole of the FBI.
Probably can't beat math, but if the FBI is running the supposed "Russian VPN" that gives them lots of information. You only have to make one mistake and you could potentially out yourself. (Assuming you don't have further layers to fall back on)
>US digital intelligence is, for all intents and purposes, a paper tiger in 2021. The whole thing is a farce to give the appearance of sophistication to act as a deterrent.
Are you willing to bet your life that this is the case?