What is a good Nf6 continuation for Black if White does not go c4?

Hello. I mainly use Nf6 as a response to d4 by White. I play the Czech Benoni when White follows with c4, but when he doesn't, I have no opening plans to go off of... I want to take back the move and go Dutch Defense instead if White goes offbeat, but of course, I can't do that. There's no overlap between the Benoni and the Dutch. If I start with Nf6, I have to commit, (...That, or waste another move going Ng8, f5.)

What should I do in case White goes for some other pawn structure like e4-d4-c3? I've tried the King's Indian before, but it also requires c4. I only have good performance on it when White closes the center with e4-d5-c4. If it's any other pawn structure, like exchange dxe5, I completely fall apart. Right now, I'm thinking of switching to the Queen's Indian, as it seems to be the closest formation to the Dutch Defense.

@1

"I mainly use Nf6 as a response to d4 by White." ++ Good

"I play the Czech Benoni when White follows with c4" ++ OK

"go Dutch Defense instead" ++ That makes no sense: either Benoni or Dutch

"There's no overlap between the Benoni and the Dutch" ++ That is correct

"If I start with Nf6, I have to commit, (...That, or waste another move going Ng8, f5.)"
++ After ...Nf6 that makes no sense.

"What should I do in case White goes for some other pawn structure like e4-d4-c3?"
++ The point of 1...Nf6 is to avoid 2 e4. Against a pawn structure e3-d4-c3 just continue developement

"I've tried the King's Indian before" ++ It is either Benoni, or King's Indian Defense

"it also requires c4" ++ No, it does not.

"I'm thinking of switching to the Queen's Indian" ++ Another one

"it seems to be the closest formation to the Dutch Defense."
++ No, closest to the Dutch Defense is... the Dutch Defense.

Make up your mind. Do you want Benoni, or Dutch, or King's Indian, or Queen's Indian?
Pick one and stick to it. All work against 1 d4, 1 c4, 1 Nf3.

Part of it is knowing which openings go together.

The Benoni and King's Indian go together, and in some areas overlap.  The reason is that they are dark square defenses (pawns start off on dark squares in the center)

Openings like the Dutch, Nimzo/Queen's Indian, QGD, are all light square defenses.

I myself play the French and the Dutch, light square defenses.  To play 1...e6 and then to try to play say, the Kings Indian, would be impossible.

My long term play, one day, is to bring the Nimzo-Indian/Queen's Indian/Catalan back into the picture.  But the way I am looking at this is I will still be able to use the Dutch against the London and the Torre, Tromp, and Colle will be basically avoided (or at least bad for White).

The key is that all defenses coordinate because they all revolve around 1...e6.

What I do now:

1.d4 e6. If 2.e4, then 2...d5.  If 2.c4, 2.Nf3, 2.Bf4, 2.e3, or 2.g3, then 2...f5.

Future:

1.d4 e6 and now:

2.c4 Nf6 and 3.Nc3 Bb4 or 3.Nf3 b6 or 3.g3 d5

2.g3 Nf6 will usually wind up a neo-Catalan and eventually a catalan.  The Neo line makes no difference if you don't play the 4...dxc4 lines.  If you play the Deferred open (6...dxc4) or the Closed, no difference.

2.Bf4 f5!

2.Nf3 f5!

2.e3 f5!

1.c4 f5!

1.Nf3 f5!

Now this is not a pressing issue, but it would be nice to have a second defense that is even more sound than the first.

The Dutch is fine, but the Nimzo is stronger.

But notice everything is about light squares.  With the Benoni being a dark square defense, you have to focus on dark square defenses against non-c4, like 1.d4 Nf6 2.Nf3 c5, which is different than the true Benoni, or KID setups.