Chakotay had 21 episodes, though? All the others seem about right, but he seemed almost as "back burnered" as Harry was.
Well, including episodes where Chakotay shared the A-plot with another character or two. For seasons 4-7, I have him down in my notes for the article as featured in:
Scorpion Pt 2 (with Janeway and Seven)
Nemesis
Year of Hell 1 (w/ Janeway), 2 (w/ Paris)
Mortal Coil (w/ Neelix, Seven)
Waking Moments
Unforgettable
Extreme Risk (w/ Torres)
In the Flesh
Timeless (w/ Kim)
The Fight (w/ Doctor)
Equinox 1, 2 (w/ Janeway)
One Small Step (w/ Seven)
Voyager Conspiracy (w/ Janeway, Seven)
Shattered (w/ Janeway)
Workforce 1, 2 (w/ Janeway)
Human Error (w/ Seven, Doctor)
Natural Law (w/ Seven)
That's only 20, but there were some borderline cases that I guess I counted differently in the final article. But yeah, most of his focus episodes are shared with another character, but that's true of the others as well. For instance, the only episodes I have down as solo Seven focuses are "Bliss," "Survival Instinct," and "Collective"; the rest of her focus episodes are shared with at least one other character.
I guess the thing is that while Chakotay got to be the featured character fairly often, his stories in later seasons rarely delved that much into his personality or backstory, since they'd mostly scrapped the fake Native American stuff by then. So it didn't feel like they did that much with him.