I have a few friends who do that I trust in this matter + I follow a lot of people on both sides of the war (support-wise) who do speak Russian and who report it into English. While this doesn't give as good a view as someone who actually speaks Russian, it still provides a good view overall and I haven't had any reason to doubt my conclusions on this matter accordingly.

Of course, you are under no obligation to believe me, and I obviously wont take offence or whatever if you disagree, it's just what I believe based on the evidence I have collated. It's impossible to be certain until proper quantitative data is put together in a good study, though.