One way that I think about it is that most people who power game and most people who don't power game
aren't even really playing the same game - they have different play goals. Ultimately, they have fun doing different things.
In most areas, this isn't a major problem - folks who love powergaming often don't love it
exclusively, and it's not like the folks who don't focus on it want to
suck, so there's a lot of points of overlap on the Venn Diagram.
But much like you wouldn't go to a horror movie for yuks and you wouldn't read Haruki Murakami for dragons and wizards and you wouldn't listen to Die Antwoord to set the mood for a date (well, unless you're me and my wife, but we're weird

), there are games that serve different types of fun (different "genres," if you want). And at a certain point on the continuum, these things do conflict.
You can't easily have both "easy, clear choices in character creation" AND "granular character-building options." If you build your game for one, the other one becomes compromised in some way.
4e was very much in the power-game genre. It gave the options and the granularity and the encounter design that pushed most power-gamers' "this is lots of fun!" button.
5e is significantly less so. It will not push that button as hard. It won't deliver on your genre expectations here.
So like sometimes you laugh in a horror movie or sometimes Murakami might do something a little fantastical, 5e can contain some power-gaming. But that's not what it's "
for," to a large degree (though individual DMs / groups can drift it more that way easily).
I think, if you find yourself completely unable to NOT play this Encounters game, I might suggest shifting your genre expectations.
Don't expect this game to scratch your power-gaming itch very hard. Don't show up to the horror movie expecting to laugh your butt off.
There are still itches it scratches REALLY WELL - socialization, role-playing, creative expression, even casual time-blowing. If you show up to get that out of the game, you won't be disappointed. Show up to the game expecting to hang out with some fellow D&D dorks, pretend to be a make-believe elf, and spending a few hours telling a fun story about said elf by rolling some dice. That's the good time you can find there.
If that isn't a good time for you (ie, if you NEED to be able to power this game in order to enjoy yourself), you're just signing up to not have fun. You could probably read a book or surf the internet or something and have a better time.