Health,
The previous topic is long and I do not have the patience to comb through it to find where the S”A says a woman has a chiyuv to get married. It isn’t in the first siman in Even HaEzer (where a man’s chiyuv is brought down).
As far as a I know the Gemara does not define Zakein and Yalda in this context. The pashtus is that a person should marry someone like them so to avoid discord in their home (see Rashi to Yevamos 106b that I cited above).
In first page of the thread you cited above, you were trying to read the Gemara to apply only to someone doing Yibum when they have another wife. The S”A I cited demonstrates that you are wrong. It seems that you are using a different out now to support your position which you arrived at without knowing the Shulchan Aruch. So please look in the mirror before you start lecturing people on m’gale panim baTorah shelo k’halacho.