xiaomi.eu weekly works only with TWRP, or? i would prefer the official eu rom if i can flash it easy with the xiaomi tool. only need language and google services
EEA means European Economic Area, that includes also some European countries (like Lichtenstein, etc) that did not join European Union
EEA ROMs are official Xiaomi ROMs for EEA countries (therefore, also for EU countries)
However, there are no such thing as "EU (official) ROMs".
Xiaomi.eu ROMs (if you are talking about that) from this forum are NOT OFFICiAL but custom ROMs - hence they are not the official EEA ROMs
If you are asking about installing the official EEA ROM, you are on the completely wrong place
This Forum (as it name states) is about the custom Xiaomi.eu ROMs
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Unlocking Bootloader is "not recommended" (as somebody stated) but REQUIRED if you want to switch the ROM (locked BL forbids any flashing - with the locked BL you can only OTA upgrade your stock ROM)
1) If you want to change your China ROM to official EEA ROM, you will of course need to unlock BL, but then you will have to use Mi Flash (and this Forum is not the right place to ask about).
And for that you don't need custom Recovery (TWRP)
2) However, if you want to go for the custom Xiaomi.eu ROMs from this Forum, you will also need to unlock BL, but then you will really need to use the custom Recovery (TWRP)