I was in the same boat as you last week, crafted alex first as people on this forum told me to do the same thing they’re telling you. I just opened up floop today.
Alex creates a huge swing and is good against almost all matchups. I found alex even helped me against zoolock, as I would clear the board, and play alex. Now they’re at 15 hp and if they can’t clear it (which zoo can’t do without a board), then they’re dead. This works for other matchups too, where alex can be used aggressively. Against slower decks, it baits their removal so they usually can’t kill malygos, plus it’s 15 damage and a giant for only 9 mana. The only downside is that a lot of decks aren’t using alex now, but that’s mostly so they can tech aggro. Also, in other variations of maly Druid like malytog, there’s no space for alexstrasza.
Floop on the other hand is very good but won’t create swings like alex can. Against aggro you just have to survive, so he can be played as a 0 mana arcane tyrant, or a 4 mana giggling inventor with a 3/4 body. Against slower decks he really helps out dealing spell damage as a second malygos. The upside to floop is that literally any variant of maly or togwaggle druid runs him. People say alex is used more because it’s neutral, but when’s the last time you’ve seen alex in a game besides maly Druid?
I main Druid so I just thought I would share my opinion. I would personally craft alex first as floop can be replaced for now with oaken summons.