KID
Opening tips against 1. d4 and other (less) common moves (black)

Semislav is imo the most solid one while also being flexible and not awfully theoretical. Nimzo and bogo indian defenses go after that in my recomendation list.

against c4 you could freestyle and play normal developing moves. but there's a problem. there's an aggressive english system called the botvinnik system. It is very effective against g6-based systems by black. Here it is:
White's plan is to castle then support the pawn push f4 and then launch a kingside attack. Often it is very potent as seen by one of my games against my friends:

Hi!
In my opinion, the choice of the opening depends on your likes and dislikes regarding the positions that arise and the time you have available for study.
Since you went for the Hippo that features a king's fianchetto then it seems to me that something more dynamic like the KID would be a good fit.
Good luck!
against 1. d4, just play the dutch defense. it's sharp and dynamic so your opponent might be put out of their comfort zone since they would now realise that you control the pace of the game.
also, with the dutch there will be a lot of confusion and tension in the air as you will be preparing an e5 pawn break and they will most likely counter with an e4 pawn break if they know their theory.
play the same thing against the english opening but it will be the anglo dutch defense. different name same setup and moves.
For 1. Nf3, try out the herristorm gambit. basically you sacrifice your g-pawn to get two pawns in the center, quick development due to tempo on the knight and loads of central space.
I am ~ 1050 rated. I am reasonably conformable responding against 1. e4, but am struggling against d4, c4, réti etc. Do you have any suggestions for openings against these opening moves? I tried semi-systems like the hippo, but they are not for me.