I was busy.
I hope with good things. I’m busy now, so I’ll try to respond to yor way of learning the gemara later.
The kasha on mem daled is how can beis din allow an ill advised marriage (multiple wives – assumed in the kasha to be unaffordable) even if there’s a mitzvah of yibum. We find similarly in the beraisa that based on the pasuk of v’dibru, beis din advises (insists) against an ill advised marriage despite the mitzvah (the example the beraisa gave of an ill advised marriage is to someone of a very different age, which will lead to marital discord
Good Shabbos