Huh, you do get what I mean. Have you ever imbibed any illicit substances, or just good narratives? (I'm hoping the answer is "both", but I don't judge.)

However, a hröa can also focus and direct the energies innate to a fëa, which could make the being more powerfu

That's a very good point.

I don’t think there’s any evidence that a Maiar with a hröa is weaker than a Maia without a hröa.

I don't think "weaker". I just think limited until the body burns up and their full might is revealed, sort of. Like if they had to fight another maia, that is. Like a huge bodybuilder in a weird costume that limits their actions, but if you actually started a fight with them, they'd just punch you "for real" and the cardboard of their costume wouldn't be in the way, it'd just tear off while they're punching you through the costume.

I would say that without a hröa, the fëa can’t be “focused” and is therefore weaker (from the wiki (no source provided):

I get your point, but I think it's more about the sort of fight that's going on. Like if you have a lense, it's not gonna make the light source more powerful, but it can focus it into a neater beam, making it more powerful in that spot, but then that focusing would mean that there's less light going around "the room" in general. Like a beam of light that's as powerful as an orb of light would burn your eyes if directed at you, but also, would be less blinding than an orb of light if directed away from you. So in that sense, the hröa being able to focus power would be a positive and a negative, depending on the type of environment/enemy you're facing.