i fear we've lost the plot on what doomed yuri means. homura and madoka? doomed. no matter how much homura tries madoka will always sacrifice herself and homura will always fail to stop her.
ochako amd toga? a hero and a villain, children on opposite sides of a brutal war. one of them was going to die in battle, and toga decided it wasnt gonna be ochako.
So. ITS NOT DOOMED IF ITS JUST A BREAKUP. FOR EXAMPLE: with the information we know about tf!ghostie and tf!aj, (and i will admit we know very little) they just broke up and aj moved on unreciprocated feelings ISNT DOOMED YURI. DONT WATER DOWN MY FAVORITE GENRE DIE DIE DIE
oh another one is zoe and reina from unstable universe. ONE OF THEM IS DEAD. DEAD AND GONE. FOR GOOD. reina is the only player left from skymore (w robin from one piece reference). literally everyone else was wiped out by cindercrest. everyone but reina either was hunted down or starved, or both in zoes case.
in all of these cases, the yuri is doomed because one of them is dead or sacrificed. they literally cannot get together because ONE OF THEM IS DEAD OR IN A DEAD-ADJACENT STATE. and ofc this isn't always the case, and there probably are exceptions where both parties are alive, but its the common one.
also... maybe controversial but its also not doomed yuri if they got together at any point during the story. if two women get together and one just dies for some reason, they still got a chance to be together! THEY GOT TOGETHER. THATS SUCCESSFUL YURI WITH AN UNFORTUNATE END.
doomed yuri is when they both. BOTH. want to be together, but they cant. AND THIS IS DIFFERENT FROM FORBIDDEN YURI.