Colle-Zukertort would have my preference over Colle-Koltanowski, though both are fine ( maybe not the best day for this statement 😁 ).
Keep in mind we are talking about systems that Capablanca and Rubinstein had played, the masters of the QGD themselves. Yusupov, a super GM of the past, had played the Colle Zukertort as well.
It's true that White doesn't strive for an advantage, though I'm not sure what's the advantage White gets in a QGD, which I play with both colours.
It's about equal positions and if one who knows their quirks and little details better than the opponent, then an advantage may come.
I'd ignore the voices that say that it's not good and if you like it, then learn it.
Also, there are some good resources to get you started on this ( Palliser has a book d-pawn attacks, Karpov has a recent book on these systems ), as well as high level games to study.
Capablanca used to play the Colle especially while he was evolving, perhaps he used the time he saved for perfecting his endgame technique ?
At some point study in the future the QGD too, because it's got many nice concepts and stratagems but the Colle is a nice system to start out with and keep later on as well to alternate your play and have the opponents guessing what to prepare for.
a : Like many sidelines or openings using the concept of playing a reversed color Black opening + one more move, of course Colle system, Bird Defense, Van 't Kruijs Opening etc. are playable otherwise they are in "the refuted category" like [as Black] Latvian Gambit, Marshall Defense or "trash category" like Damiano Defence.
Now is it a good choice ? It depends notably of our philosophy of the chess game . For example I can play with White 1) d4 d5 2) c4 c6 3) cxd5 cxd5 and of course is playable but I think not in line with the philosophy of seeking to play an opening from advantageous position.
b : Obviously I'm not a gosu etc. so I can't demonstrate an advantage but just playing against a strong chess program is enough I think to get an idea of QGD problems.
Otherwise after 1) d4 d5 2) c4 e6 on the simple 3) cxd5 exd5 we can see an imbalance to the position and for ex. a simple plan like a minority attack says to me, it's not really equal (and the exchange variant is not the most ambitious so it makes optimistic for White).
c : I believe the study or the endgame technique is the hardest thing to do in chess and it tends to annoy because we have to calculate and be precise (tiring), it can last long (endgame of Queens, lot of chess for ex.)... so in short if Capablanca played Colle system for perfecting his endgame technique, I think it convinces rather not to play the Colle system
(ps : We say Colle system but in reality to avoid confusion we should say Colle-Zukertort system because it is almost always this one that is played)
Yet another prophet. Ding won against Nepo a few minutes ago with the Colle- Koltanowski...
yet another game where Ding played the opening to draw and didn't manage to achieve his goals😁
To be fair, the result had nothing to do with the opening. Ding managed to get an exremely complicated position on the board, where mistakes by both sides were inevitable. It was a risk that paid off, and the lesson learned is that chaotic positions may well occur from very quiet, "unambitious" openings.
True, but this means it's a fine opening to create complicated play as well, for me i.e. it came as a surprise, I had the Koltanowski into my "calm & solid" mental bucket, would play it, if e.g. the opponent is not familiar with these positions from the White side of their repertoire.
It was not an opening win indeed, nothing wrong with that !