If you make dirty flashing then you won't lose your data. Dirty flashing I mean to flash direct the ROM via Twrp without making any erasing in data or in internal partition. Also you said that you tried via fastboot and you had bootloop. It is logically because you had 13.0.3.0 which is EEA ROM and instead to flash again EEA ROM (like the fourth link which I said you to flash), you flashed the 13.0.5.0 which is Chinese version and for this reason you have now bootloop. The question is that when you tried to flash the wrong Rom in fastboot, did you select the second option which is for keep your data or you left the default option which is "Clean all" (clean flashing - erasing all partitions) ?Will I lose my data if I install a previous version? I'm trying to keep my data intact