Having a smartphone w/o Google stuff sounds very promising but I find it really hard to collect bits and pieces to answer the one true question:
Can one have a phone device with /e/OS installed and working properly in Greece in 2026?
Are the Greek mobile providers supported?
Are there any modern (2025, 20206) devices other than Fairphone (which is really expensive) supported?
What general / government / e-banking apps are supported in 2026?
Answers to those questions should be about hardware available on the market in 2026 as well as the latest software (app) versions available. Various forum lists either contain outdated information or do not mention Greece at all.
/e/OS is built on LineageOS, which is built on Android Open Source Project. Installing it doesn’t alter any phone’s modem in any way. So if any particular regular Android phone has the frequency bands that match a mobile service provider in Greece, then the same device running /e/OS will, too. If VoLTE is required for calling on Greece’s networks, then the device also must support that and be approved by your network; /e/ can’t add it or subtract it from the original device’s capabilities.
Therefore, what you have to do is find a device that fits your needs, confirm it has an available /e/ build (either official or unofficial), confirm its frequency bands match your chosen network in Greece, and potentially confirm it’s VoLTE-capable on your network, if that’s also a requirement - and it will be soon if it’s not already required, as 2G and 3G networks are rapidly disappearing. (VoLTE = Voice over LTE networks, and it’s a calling technology, not to be confused with LTE data.)
This will require some personal research, and responses from actual /e/OS users in Greece. But remember, there’s always browser login if a banking app doesn’t work in the absence of Google spyware.
Note that all Samsung phones lose their VoLTE-functionality if the original OS is replaced with a custom Android ROM, due to their proprietary implementation of IMS services. That’s the current situation anyway. So I wouldn’t choose a Samsung.
