Edit: to clarify, I have no problem with the event being the MSQ. That's awesome, I love it. What I want it to not be locked out of the current event quest because I haven't finished the prior chapters of the MSQ.
Genshin started this way too but they've since implemented a warning that says something like (paraphrasing) "You're not caught up enough for the event quests to make sense. Are you okay with spoilers?" And if you are, you can proceed with the event quests! (Thank you genshin!)
Infold has already shown that you can temporarily use unattained abilities for specific quests/domain challenges. My alt didn't have sticky claw yet but could use it for the red riding hood event domain thingys (I'm so articulate, I know 😆).
I literally made my alt so I could enjoy the MSQ at my own pace because I joined in patch 1.8(?)ish and had to speed through to get caught up enough to play the event.
Side note: i do really appreciate that they seem to be trying not to disable too many skills for the new dresses coming out. Not perfect but better than before! (I'm looking at you, fairy dragonfly dress that can't be used with archery OR purification 😒)
FYI, im not mad about this! 🙂 Just wistfully wishing I could take my time.