Just try learning all of those things. (At least that's what I'd do)
Can't decide what openings to play
The point of the openings is to get to the middlegame. You need to reach a middlegame position you are comfortable with.
But as a general advice, you should start your games with 1. e4, since first you should play open games. And certainly you can't decide whether you are a tactical, or positional player. You need to become a strong player first, you need to be able to play open and closed, semi-closed positions well, and only after that can you decide if you are a positional or tactical player.

Can't decide? Then do what I do and play whatever opening you feel like. Who knows, you might eventually come up with a solid one of your own.

I do play whatever openings I feel like, but I just want to stick with a few and "master" them lol. And for e4 I have played many many games with that, and quite a few with d4. And I'm way more comfortable playing closed games than open. I understand the plans of the pawn structure a lot better.

e4: Allows sharper tactics and is widely considered the single best first move in terms of activity and development
d4: Allows more positional play. However, White maintains some flexibility and this move can open up into sharp tactical play. d4 has also had slightly higher success for White.
e4 and d4 are the two most common White opening moves. But since you enjoy playing closed games, then stick with d4 and avoid tactical captures that your opponent will likely throw your way. The plus side to d4 (for me) is I avoid the Ruy Lopez main lines which have been thoroughly gone over in past years.
Finally, if your opponent counters d4 with the popular Nf6 (Indian Game) then you as White have a massive amount of tactical choices at your disposal.
For instance: 1. d4 Nf6 2. c4 with the idea of Nc3 and a e4 pawn push threatening the Knight. If your opponent plays inaccurately then things can get tight on his side of the board very quickly.

If you decide to go with 1...e5 as black the 1.e4,e5 2.Nf3,Nc6 3.Bb5,Bc5 variation of the Ruy Lopez is easy to understand and execute, or the 3.d4,exd4 4.Nxd4,Nf6 variation of the Scotch. 4...Qh4 is a sound surprize weapon, whereas 4...Qf6 may lure the opponent into a false sense of confidence as he may think, "lol, queen out early, what a patzer". It's important to understand the ideas behind these moves though.
For black the Nimzo and Queen's Indian seem safe and flexible against 1.d4.
As for what to play as white play what your mood dictates. But as you've stated you want to commit to one system, nothing wrong with that.
1.e4 is initially fun for the first few moves, then things sterilize or otherwise get mathematical usually.
1.d4 on the other hand has a certain flexibility to it where tactical complications can blow at any moment as long as you keep things imbalanced. Alekhine and Marshall have great 1.d4 games worth looking at. Fischer for 1.e4.

Depends on where you are at the improvement table: If you want to improve, then 1. e4! followed by playing a sound opening like ruy lopez. The idea is to get AS MANY DIFFERENT PAWN STRUCTURES AS POSSIBLE. So not the exchange ruy lopez, where you will get 1 or 2 main structures, but rather d3-c3 lines or the main line.
So:
1. e4:
1.. e5: Ruy lopez d3-c3, ruy lopez main line, italian with d3-c3
1.. c5: Open sicilian, or c3-sicilian. Maybe the Smith-Morra. Gambits is quite good for improvements.
1.. e6: Main line, or the exchange followed by 4. c4 (to get IQP, which is a very important structure to learn with both colours)
1.. c6: Exchange (to learn the Carlsbad Structure), Panov (IQP again), open (Tactics) closed (d4-e5 structure)
If you think you just want a solid setup, and improve your results (not improving so much overall), then a solid setup like the Colle is fine. Or exchange ruy lopez. Or whatever fits your style. But my advice if you want to improve: Learn as many diffrent structures. My advice if you want to get better results: Specialize in 1 or few structures.
DeathBySquirrels589, 7... Nxe4 and black is up a pawn.

At your level, learn tactical play first. Forget about positional play until you are 1800. e4 as white is best to learn tactical play. For black d5 against both e4 and d4.

DeathBySquirrels589, 7... Nxe4 and black is up a pawn.
If Nxe4 you fall into a simple ponziani trap with bxb4 nxb4 qb3 nc6 and bxf7
You could choose an opening or two that you like for both e4 and d4. This way you can switch between them (this makes you unpredictable!). Or say for example you are strong playing 1.e4, but good at 1.d4 as well. You can pull out a Queen's Pawn opening as a surprise attack if you need it! It's great to be able to switch between the two at tournaments too.
Try testing the waters with both openings and figure out what style of play you prefer: do you like sharp, aggressive tactical games? Or quieter positional play? They say 1.e4 leads to tactical games and 1.d4 is more positional and leads to closed games (this is not necessarily written in stone (I almost exclusively play 1.d4 and don't usually run into closed games), but is at least something to go by).
But all in all, it's up to you and you'll have to see what works good with your playing style. Anyway, good luck! : )

Why don't try C4?
No. Same suggestion as above.
1. c4 is not only about positional but there are many things involve. And some times with 1. c4 you want to trade your R, B, N with pawns, B, or N.
I am not good at 1. e4. I cannot play it vs 1600+.
Hello,
I'm a player who cannot decide what opening to stick with and learn, but more specifically, I cannot decide if I want to use e4 or d4 to start my games. I have more experience with e4 but I like d4 just as much; therefore, I cannot decide one to stick with, then after I find one, I would like to stick with 1 or two openings and just master them. I'm also unable to decide if I'm tactical or positional, so that doesn't help me either. Any and all help would be greatly appreciated!
Thanks,
Doug