As for further integration, would be interested in which of countries not in Eurozone end up joining as no one in last 5 years has joined. Technically only Denmark can stay out indefinitely but doesn't seem like EU is enforcing this.
For those who have studied economics, most know you cannot have a common monetary policy without a common fiscal policy so any chance of EU moving towards one? That would mean EU wide taxation (like US and other federations, countries would also levy taxes although at much lower rates than now to offset taxes paid to EU) and EU will borrow instead of member states? This seems like a good idea economically but I would think it would face a lot of pushback.
Well I am only somewhat qualified to answer these 2 so here it goes.
Regarding further eurozone expansion I am actually quite optimistic on it. There are 2 countries that are actually on track to join the eurozone in the near future: Bulgaria and Croatia. Bulgaria might seem like an odd pick but their currency is already pegged to the euro so it barely makes a difference; while Croatia seems like a more normal candidate. Allegedly Croatia plans to join the euro in 2023 and Bulgaria in 2024 even if ironically euro support in both seems a tiny bit under 50%. I am not sure if they will achieve their targets but unless public opinion radically changes or something, I believe Bulgaria and Croatia will join the eurozone some time in the 2020s
Beyond those 2 Denmark and Sweden are near certain to not join the euro at least not any time soon in my opinion.
As for the 4 remaining Eastern European countries I can't imagine the EU wanting to further integrate Poland or especially Hungary given their current governments; though neither of the 2 seems to want to join the euro anyways (plus in Poland it seems it would require a 2/3 supermajority). Of course it is possible that the governments of these 2 might eventually change but I don't expect them to adopt the euro any time soon either.
That leaves only Romania and the Czech Republic as long-term candidates for euro adoption. In particular Romania seems to be willing to adopt the euro even if it is dragging its feet; but I am confident they will eventually bite the bullet, possibly some time in the late 2020s or early 2030s. The Czech Republic is slightly better but I think public opinion is very much against the euro (even if it'd be the country to benefit the most). I don't think they will adopt the euro any time soon but if they do it won't be in the next decade.
In any case, my guesses for euro adoption would be:
Croatia: 2023-2025
Bulgaria: 2024-2026
Romania: Some time around 2032?
Czech Republic: Very far into the future, if ever
Poland, Hungary, Denmark, Sweden: Never
The 2nd question is actually simpler to answer. There have been attempts at a united fiscal policy since the Great Recession and Greece's debt crisis; but many people see them as attempts by indebted Southern European countries to get their debts paid by rich northern countries and are therefore opposed by the "austerity bloc" (most recently composed of the Netherlands, Austria, Sweden and Denmark iirc)
Iirc the EU finally bit the bullet and made some common "eurobonds" as part of the covid stimulus package but this seems to be a one-off thing that won't be permanent.
I am quite pessimistic on the EU getting a common fiscal policy any time soon. In any case the mid 2020s will be interesting as southern european countries will have to start paying off the debt