I would recommend running untrusted proprietary software as a webapp if possible, it will not be able to be as intrusive in that case compared to native app even with all the sandboxing (flatpak, snap, etc…). Or Virtual machine as the most secure option, but it may be overkill.
In war you can have all the advantages you can think about and still lose. Overconfidence about military supremacy has a huge cost if the war proceeds.
Germany in WW1 entered it avoiding attempts at deescalation, because it was overconfident it would overwhelm France and Russia. Both France and later USA had to withdraw from Vietnam. For recent example Russo-Ukranian war had Russia at clear advantage in manpower and industry, but we know now in retrospect, that it was not a couple of week pacification campaign as even myself was convinced it would be.
I guess that statement was likely a diplomatic posturing, but keep in mind that military conflicts very rarely go according to plan. The only certain thing that happens is human suffering inherent to military conflicts.
World without borders, is the world without escape. Now we have different jurisdictions, which limits the reaches of power of governments. You can move to a country with less oppressive laws, or at least get news from there. Different jurisdictions makes things like TOR and VPN work for censorship circumvention and privacy.
Besides earth federation would subvert any diversity we as humanity have. I would prefer more small countries gaining sovereignty than big empires(federations) growing. Power should be decentralized, not the opposite.
Fascist and colonial states atrocities are widely documented in Wikipedia, countries that we consider capitalist probably too. I recently stumbled across Belgian atrocities in Congo reading Wikipedia by accident. It motivated me to read more about it in the future, maybe “Heart of darkness” (while not exactly historical, it still seems like a good critique. By the way is it a good novel?).