If it wasn't in NATO or the EU, Russia would've already invaded by now, that's obvious enough.
But they are in NATO and the EU, so they appear to be safe. Russia invading Estonia would give the US and other NATO powers effective free license to start hurling missiles themselves (instead of just handing them to Ukraine).
I don't see how the US entering the war would be equivalent at all. Russia's army can't even handle Ukraine's army after they've been hastily handed a bunch of random Western equipment, the US would zero issue manhandling the Russia military.
There's already NATO troops in Estonia, the US has a bunch of troops relatively nearby in Poland, and when Russia invaded Ukraine recently, the US knew months ahead of time. Given that the US is in a military alliance with Estonia, Russia won't dare invade in the first place.
Estonia is in NATO and the EU right? I think a Russian invasion of a NATO country would be a problem if you lived anywhere in Europe, or the world really.
In the EU, maybe? But there are at least three countries currently partially occupied by Russia (or "pro-Russian" forces), and none of those are Estonia. Estonia also enjoys the security guarantees that come from being a NATO member.
Estonia is a member of NATO, so it "doesn't matter", in the sense that Estonia being a target means that all other members of NATO are a target. Of course practically speaking it is a bigger issue for Estonia than for say Canada, but at least within EU, I would not let that aspect be a major point in deciding places to move to.
The Ukraine conflict made it clear that Russia bluffs its capabilities pretty severely.
They frequently make statements that can be construed as threats to EU and NATO states, eg. some jackass in the Duma saying they don't recognize the sovereignty of the Baltic states. A few years ago it seemed like it might not be a bluff. And with Donald Trump openly bashing NATO... It would have been conceivable that Putin could attack and assume the west wouldn't care.
But the Ukraine conflict made it clear that it's not possible. The west cares, and the Russian military is pretty weak.
But they are in NATO and the EU, so they appear to be safe. Russia invading Estonia would give the US and other NATO powers effective free license to start hurling missiles themselves (instead of just handing them to Ukraine).