For updating (not first time installing) Xiaomi.eu Stable you don't need wipe or format Data.Ok, I understand, looking where you tell me I think I have the latest stable version and no other has come out, I got doubts when I now saw users talking about a more recent version, but possibly it is for another device. As you comment, I understand that I will receive a notification with the update when there is one, what I did not know is that you had to use twrp to update, I thought that the method was the same as the original miui, I suppose that doing it with twrp will not be necessary to do any data erasure and you will be able to keep what you have on the phone, I suppose it will be like that, maybe I'm wrong.
Thank you.
Greetings
Specially for Mi 9T that is coming to its end of line - don't expect MIUI 13 or A12 or so.
Probably, there will be one more small and final Stable update, with the newer Security patch and maybe MIUI 12.6 (since Mi 9T Weekly were for months on 12.6, and next week Mi 9T will rceive its final Weekly)
Hence if you don't force wipe or format Data in TWRP (do not do it, no need for), you will not loose any data