Putin's global strategy is to revise the current state of international relations and move Russia a step up. For this, he needs to push the United States out of Europe, try to fragment Europe, and bring the relations with these fragments to a state, where Russia has more authority.
One of the steps towards ruining the international order are Russia's actions in regard to Ukraine. Putin has violated almost all international order standards, and has had no response. Everyone saw that international order is non-existent, and that international security institutes, both global and regional, have no means to respond. This is what he wanted.
Alone, Ukraine cannot defend its sovereignty and recover its territorial integrity. This requires a coalition of fellow-countries, ones that support the return of international relations to the former state. So, we need to establish very close relations with East European partners and, in general, with any countries that hold this international order important.
In this regard (it is not without reason that we talk about hybrid warfare), Russia is waging a strong informational war, launching propaganda, a stream of lies, double-dealing, fakes, which makes it very hard to separate "us" from "them".