How to force queenless or closed/strategic positions with White

Thx for all of the good advice! Indeed I will try 1.d4 and have a closer look at the following variations (in case there is someone like me out there who's interested). I'm intending to still play objectively good openings to be able to evolve as a player and not just play some system.

QGD: Exchange Variation with later Bg5 vs 3.Nf6 and Bf4 vs 3.Be7

This is a good choice, as it usually allows white the choice of two good plans: a3/Rb1/b4 with a minority attack, or Nge2/f3/e4 with expansion in the center and a possible kingside attack. I have obtained many great positions with White using the second plan. See the games of Botvinnik for some examples/inspiration. The Catalan is also a good choice, but due to its less forcing nature it allows Black a greater variety of set-ups, and is less strategically straight-forward, and thus takes much more study time IMO. Perhaps save it for once you have a couple years of 1.d4 under your belt.

QGA: Quiet setups with 3.Nf3 and e3

I am sure this is fine but won't comment as I have only played 3.e4.

Slav: The one I'm still not sure about. At the moment I found nothing more suitable than the exchange with an early Bf4 (admittedly it can get quite dull)

I'd look for something else here if I were you, as it is important to press for an edge with White. Either play the mainlines and find something you like against the Slav, Semi-Slav, and Chebanenko Slav, or play 2.c4 c6 3.Nf3 Nf6 4.e3, which is more positional. Often white will go for the bishop pair if Black plays his bishop out to f5 followed by ...e6 (with Nh4).

Nimzo: Classical with 4.Qc2

This can get pretty sharp in some lines, and White has to be ready to accept a position where he is quite far behind in development in some lines (you get space + the bishop pair but it can still be quite tricky to finish your development safely). IMO White has very little chance of getting a theoretical edge against the Nimzo anywhere (part of the reason I am learning the Catalan with White) but 4.e3 is certainly a good choice if you want to put Black's knowledge to the test without entering the complications that can arise in some of the 4.Qc2 lines. If nothing else, my limited experience with 4.e3 makes me think it is a bit easier for White to play than Black.

KID: Smyslov/Petrosian line (thx TitanCG for the tip. There are many interesting games from Akobian in this one). I like this one a lot - it should frustrate the typical KID-player because he usually has no attack.

I am not familiar with this line, but the fianchetto variation is also good for stiffling Black's kingside attack as far as I know.

Grunfeld: Setups which keep the center with e3

Again, I am not familiar with this, but I would expect it to frustrate many Grunfeld players who are used to more open positions that involve White having a big pawn center.

Benko Gambit: Lines that involve pushing to b6 instead of grabbing the a-pawn. Objectively nothing special for White but Black's a-pawn stays weak and White seems to have the clearer plans.

I have no experience here either but at a glance I would probably prefer White. If you are feeling like studying a bit of theory, and often defending your queenside/center for the first part of the game, then the line where White accepts the pawn, followed by fianchettoing his king's bishop, is quite challenging for Black to deal with and really questions the viability of his opening gambit IMO. It can go horribly wrong for White if he is not precise though (still happens to me once in a while)!!

Benoni: Since I think this is just good for White I will not shy away from it but experiment  with lines that involve early f4

These lines are certainly challenging for Black, but don't seem to fit with the style of play you are trying to achieve. Personally I would recommend looking into the Modern Mainline or the Fianchetto variation -- both are theoretical but fairly challenging for Black, though the Taimanov variation (f4 followed by Bb5+) certainly is as well. It really depends on how aggressive you want to play here. I play the Modern Benoni with both sides and personally I think Black is basically fine in all lines (maybe slightly worse but not more than that). 

Albin Counter Gambit: 4.a3 seems to limit counterplay

I would recommend 4.Nf3 Nc6 5.a3.

Dutch: 2.Nc3 lines look interesting

A good choice. 2.Bg5 is also good, as are the mainlines with g3/Bg2 if you don't mind giving Black the choice between Classical/Stonewall/Leningrad setups.

against 1...e6 I go for the French which I play with black, so I at least know something about it

If you do decide to play the French with White, then I would suggest 3.Nc3 or the Tarrasch variation. 2.c4 would probably be less work to play, though Black may try to get into a dutch with 2...f5, while avoid your 2.Nc3 anti-Dutch system.

A late "thank you" to all that responded, especially BigTy! I'm trying the above lines over the board at the moment and it seems to work out quite well - I'll continue gathering some sample size but I'm happy with them for the moment