The EU has been sick for a long time the refugee crisis accelerated this sickness with the lack of action form the EU. The rise of Right-wing parties in member nation within the last 6 years with major countries like the UK, Poland, Hungary, Italy, And Austria all seeing their people voting in right-wing coalitions. This causing said countries disobeying the EU on policies like shared refugee/migrant responsibility by accepting quotas of these people. Brexit shocked the EU showing that a nation could leave it the people willed it and with Poland and Hungary coming under attack with the threat of possible sanctions because they refuse to accept the refugees/migrants break could start.
I see The Visegrad Group (Poland, Hungary, Czechia, Slovakia) leaving all around the same time. A while later Italy and Austria could leave since there right-wing allies left the EU could threaten them easy're. At this point I see countries like Romania, Bulgaria, And possibly the Baltic States leaving due to Visegrad and Russian Influence and EU crackdown on members. After this I think the EU would try to crackdown on its remaining members which would make smaller members very resentful like Denmark and Portugal and I see them leaving and the EU either completely collapsing or shrinking into a smaller organisation with basically Germany, France, Sweden, Maybe Spain, And the Low Lands.
NATO would lose several members assuming Donald Trump is reelected which is what I see. The Members I see likely leaving are Germany, France, Netherlands, Belgium, And Turkey. I see the Visegrad Group becoming a economic pact and expanding in former Eu members in Eastern Europe and Austria and Italy. NATO would focus more on Defense of Eastern Europe from Russia trying to exploit a weakened Europe, Turkey against Greece, And Germany and/or remaining EU Nations. NATO could expand its members to Asia and other continents, But that is off topic.
Overall the EU would collapse mostly or completely in the near future. Leaving Europe weakened for Russia and other outside influences. Also NATO would also be weakened, But would be more focused and for a time more ideologically united.
Long ago all of Europe was in brutal war against each other. After surviving such a horrible phase the leaders decided to unite as one free trade group and to permit easy interchange of people and ideas.
And the economy grew and the Euro was becoming mightier than the dollar.
Except some small nation run by absolute bad leaders decided that they could do whatever they wanted and abuse the Euro. Then a flood of migrants happen and rather than to work together and deal with the problem, They started passing the migrants and closing borders. And then rather to commit and work together through these time some nations decided to break away from the EU.
You are going backwards and your isolation will become your weakness. Why would other nation help a nation that left.