I use a VPN service to access my accounts in Europe. It is more secure than most WiFi’s.
+1 this......I did this when I lived in Milan - I was able to watch streaming US TC like PBS, etc. NordVPN.....
As to OPs concern, the main restriction on staying overseas is the visa limitation - in Germany it is 6 months. They will require a resident or some other such visa to stay longer. In Asia there are similar restrictions....people do 'border runs' to get stamps in their passports to mitigate that. I don't know if the 6 month restriction is EU-wide. About 15 years ago, my ex-husband would make a border run from Poland to Germany to get the stamp and then go back to Poland as he was living and working in Poland at the time (3 years).
I've had some issues with using credit cards in Europe, but only because the banks want to know where you are going and certain countries are notorious for scams: Albania, Croatia, etc. I have had issues being able to log in to my email accounts from Croatia.
I usually land in Frankfurt, take out a bunch of Euros in cash and then use my credit card for hotels, rental cars and large purchases. Otherwise I use cash. Same thing in Great Britain, etc. I went to Portugal, Germany, the Baltics (all three) and Sweden this year and had no problems. I was gone a total of 5 weeks.
Get a credit card that does not have a fee for international transactions.