We have troops and missiles in Ukraine? I mean under our direct control. Providing weapons for Ukraine to use isn’t exactly the same as the USSR putting nukes in Cuba.
First let's have Russia pull its troops out of Ukraine, re-affirm the binding agreements it has already signed to permanently respect its sovereignty (and amend these for additional guarantees as needed), and commit to a timetable for reparations -- with a substantial downpayment. At that point, we can have a discussion about such matters.
Until that happens - Russia has no "legitimate" security needs whatsoever.
Not that this means NATO should start putting missiles in Ukraine willy-nilly. But really, until the above happens -- one needs to just drop the word "legitimate" from one's vocabulary, as it applies to current regime's wants or needs for anything.