Lemmy as a whole will probably take it. Lemmy.world might have issues because it might melt down and the private instances with an approval process like beehaw will just ignore it since their manual application queue can't handle it.
You might be surprised, the usershare breakdown of Lemmy is pretty darn decent
True, lemmy.world still makes up ~1/3 of the pie, but even if it goes hard-down, that still means that the majority of Lemmy will remain online & functional. It's important to note that each instance stores a copy of external posts & comments, so brief outages might not even visibly affect users from other instances who subscribe to lemmy.world content.
Also, FWIW: lemmy.world is run by experienced operators who've previously weathered the Mastodon surge. As far as bulletsponge instances go, lemmy.world is probably the best candidate we could have hoped for considering how grassroots this all still is.