1.d4 is indeed the best first move


I NEVER played d4 in my life xD im learning the kingsindian attack right now with White against caro-kann defence, france defence and the sicilian defence

I don't think this person is @StupidGM. He does have some legitimate points. For example, there are many more options for both sides in lines after 1. d4, and most of the positions are very rich.

If you are serious about gaining the maximum chances to win a game as white you have to play 1.d4. It is by far the best for multiple reasons.
It is very dynamic, you can play sharp lines or play very safe and calm lines depending on what you want.
It is very very complex, there are a lot more choices than for example in e4 lines. Alone against the Kingsindian Defence White can choose between 10 continuations which then subdivide in multiple different ways to follow up.
It is a must play if you want a draw or equal position against a stronger player. Playing d4 allows you to get dry and equal or at least very balanced positions by force if you know how. If you play 1.e4 black can for example play the Sicilian which WILL lead to imbalanced and sharp positions which favor the better player.
With 1.d4 you can build up a repertoire with a lot of dynamics, where you can choose between different options. For example instead of always following the mainlines you can also go with the Veresov or Colle or Trompovsky. You can switch move orders in most 1.d4 variations which gives you extra options.
If you are decently booked up with White as a 1.d4-player you can not have any trouble in or after the opening.
Period.
I agree with you. The main reason why most books recommend 1.e4 is to learn tactics. I see the point. However, with 1.d4 you are doing something similar to the King's Gambit without any risk (challenging the center, pushing the pawn on c4 before playing Nc3 and so gaining space, preparing to open the c-line, etc etc etc). Weak players facing the Queen's Gambit have usually no idea how to proceed with the black pieces, but usually they have some concepts how to play against 1.e4.

If you want to invest time and a little bit money to learn 1.d4 I recommend to you

I hate Sicilian and French, so I don't play 1. e4; I hate playing against Slav or Nimzo-Indian, so I don't play 1. d4. 1. c4 is where it's at!

The advantage of 1.c4 over 1.d4 is that most people will know even less what to do against 1.c4. I had also a lot of problems with Nimzo-Indian and against the Slav and Semi-Slav, but I know now a little bit better how to play against these defences (this is for instance my case). In the Slav I avoid the very sharp variations and I know how to get the pawn back if Black plays ...dxc4. I am still struggling to find the right move orders in all these Slav defences, as for instance the Chebanenko, the Schlechter, the Semi-Slav, the Triangle Variations, etc. In the Nimzo-Indian I develop the Queen early (5. Qc2) to avoid getting double pawns. Actually the Nimzo-Indian is a kind of gambit, although nobody call it like this, since Black is giving his bishop-pair in several lines in this defence.

I NEVER played d4 in my life xD im learning the kingsindian attack right now with White against caro-kann defence, france defence and the sicilian defence
The KIA is great, of course, as it is very straightforward and rather easy to learn. I have even a book on it: The KIA move by move, by Neil McDonald. The author is really good in his explanations, it is one of the best openings books that I know. Nevertheless, I decided to go back to my 1.d4 because this is the opening that I invested a lot in the past, and I thought I could try to get deeper on it.
If you are serious about gaining the maximum chances to win a game as white you have to play 1.d4. It is by far the best for multiple reasons.
It is very dynamic, you can play sharp lines or play very safe and calm lines depending on what you want.
It is very very complex, there are a lot more choices than for example in e4 lines. Alone against the Kingsindian Defence White can choose between 10 continuations which then subdivide in multiple different ways to follow up.
It is a must play if you want a draw or equal position against a stronger player. Playing d4 allows you to get dry and equal or at least very balanced positions by force if you know how. If you play 1.e4 black can for example play the Sicilian which WILL lead to imbalanced and sharp positions which favor the better player.
With 1.d4 you can build up a repertoire with a lot of dynamics, where you can choose between different options. For example instead of always following the mainlines you can also go with the Veresov or Colle or Trompovsky. You can switch move orders in most 1.d4 variations which gives you extra options.
If you are decently booked up with White as a 1.d4-player you can not have any trouble in or after the opening.
Period.