Imo only the US, China and partially Russia (and maybe India) can be really autarchic, all of these countries that span almost an entire continent (or a big part of it).
Not sure if there's a solution to all of this, from Europe's point of view. Ideally by this point we should have had a genuine political and societal union (I'm from Romania myself, another EU member), but that has failed, it is failing (of course that the powers that be refuse to acknowledge that). Without that genuine political and societal union one cannot have an autarchic Europe.