Why would Russia flip from trying to get people in the US afraid of 5G to trying to calm 5G fears? I have no idea.Russia has no opinion either way and you're mis-interpreting everyday journalism as some kind of massive conspiracy, which is why it makes no sense.
I looked at the first video in the comment you link to. The story is actually "Group of scientists warn 5G network can pose health dangers", and provides a clip of Dr Sharon Goldberg talking in the Senate about 4G as evidence.
She says:
"Wireless radiation has biological effects, period. This is no longer a subject for debate when you look at PubMed and other peer reviewed literature."
and goes on to cite a bunch of papers that (she says) look at the effects.
As far as I can tell she's some sort of doctor who campaigns against mobile towers.
Now look at it from the perspective of ordinary journalists. RT tries to find stories that are interesting yet 'under-reported'. Imagine in this case there are no Russian masterminds or calls from Putin; just everyday journos who have to fill airtime with something. The clip starts with the host of the show basically admitting he has no idea what 5G is, that he's not a technical kinda guy, he only heard about it that afternoon and his entire knowledge of it comes from reading the summary on Wikipedia. His angle is "it sounds too good to be true so where's the catch?". Some random correspondent then launches into the clip of the doctor.
You don't need any fancy conspiracy theories to understand what's going on here. All you need are people who know nothing about technology looking for something interesting to talk about. They see "experts" testify before Congress citing the peer reviewed, published papers of other "experts" (journos know that this is the gold standard), and that's their permission to talk about it.
All we're seeing here is the fact that you can find peer reviewed published academic papers for a huge array of bizarre ideas. It's just not a serious filter on the flow of research but journalists don't know that - academics themselves are forced to filter it using entirely subjective notions like perceived reputation, which can vary wildly depending on who is asked.
The only reason RT specifically seemed to focus on it is their pitch is that they are outside the CNBC/MSNBC/CNN/etc groupthink.