It was a major factor but there were others, mainly the proximity of NATO troops to Moscow.
***Estonia was in proximity to Moscow, why didn’t Vlad the Imploder invade them? Because they were part of NATO, that’s why. Bullies don’t pick on those who have protection.
Also, Estonia doesn’t have such yuge oil & gas reserves. Russia didn’t say much about Ukraine, even just plain ABANDONED their nukes there, when they were disintegrated. 3-4 years after that disintegration they sign the Budapest Memorandum. The Ukes HONOR that agreement, then oil is discovered and now allofasudden Vlad has a problem with supposed NATO sites being 200 miles closer to Moscow than they were before. What a pile of bullshit. This is about oil.
According to the video, if you watch it, when the Baltic states were added Russia was in a very weak situation militarily and economically. I am not a foreign policy expert just telling you what was in the video so you won’t have to spend 90 minutes watching it.