Android shouldn't be considered Open Source anymore, since source code is published in batches and only part of the system is open, with more and more apps going behind the Google ecosystem itself.
Maybe it's time for a third large phone OS, whether it comes from China getting fed up with the US and Google's shenanigans (Huawei has HarmonyOS but it's not open) or some "GNU/Linux" touch version that has a serious ecosystem. Especially when more and more apps and services are "mobile-first" or "mobile-only" like banking.
I see where you're coming from, but companies like Google have local legal representation (e.g. in Ireland for the EU), and have to operate under EU rules if they want to do business here (just like how a EU business has to operate under US rules). If the EU says that you should be allowed to do your own thing - and they have - then Google can either comply or leave.
Don't attribute more power to companies than they have - they want you to believe they can get away with this, but don't echo their rhetoric.
What does have weight is the European Union, which Croatia is a member of. If the EU parliament makes a law that Google is not allowed to have these kinds of rules and do business in the EU, then Google will listen. Given the horrible state of the US government, the EU is just about the only force left in the world able and willing to stand up against these tech giants in a way that forces them to pay attention and act responsibly.