Something is wrong with the way I play chess and I don't know what it is

The title is pretty self-explanatory. I play chess often (at least since I came back), I think before I move (sometimes), and heck, I try to use tactics all the time. However, even though I do all of this, I still win (possibly slightly less than) half my games, and I don't know why. Maybe my thinking is just wrong sometimes. Maybe I try too hard to get what I want. Whatever it is, every game I play, I manage to make at least one massive blunder.

(Don't mind the name, I made it when I was genuinely bad at chess.)

All youre playing is speed chess. How do you expect to improve?

That's a classic sign of hitting a plateau, and the key is often not what you're thinking about, but how you're thinking. A simple but powerful technique I have my students practice is to develop a consistent thought process before every single move, especially by asking, "What are all the things my opponent can do in response to my move?" Making this check a disciplined habit is often the thing that turns those game-losing blunders into winning advantages.

I'm still taking a look at your games and will probably come back and edit this.

You say you try to use tactics all the time. But of the games I've looked at so far, you are missing basic stuff, like capturing free pieces that your opponent blunders. While tactics are great and without them you won't reach 1200+, zero tactics but following good chess principles and not blundering plus taking free pieces will get you to 750. Probably higher. You don't need tactics right now.

edit: More thoughts. I just watched this game. https://www.chess.com/game/live/141969386054?username=eloratingisnegative. Move 10 you needed to recapture a bishop to maintain equality. Instead you captured a pawn, allowing their bishop to get away. Move 11 you threw away your knight with Nxf7, which if you are calling that a tactic, it did nothing. No more sacrifices. How often do they work for you? I'm willing to bet (because I was once your rating too), not very often if you review your games. Once your calculation skills get better in the future, you'll know when to and when not to make sacrifices. But you aren't there right now. Even for me - I'm 1300 and whenever a little voice in the back of my head tells me to do some crazy sack, most of the time I don't listen. It might be fun and exciting, but at your rating, I think you should try to have more self control and don't ever sacrifice until you get over 1000. It's not needed to reach it.

Here's another game. https://www.chess.com/analysis/game/live/142059477910/review. Move 7 you hang your bishop. Move 8 we get Nxe5 where you send your knight to die over a pawn. These are not good "tactics". You can't blow open a position and lose attacking pieces and expect to be okay if your opponent knows what they are doing. If you need to do a pawn break, use your pawns to do it.

https://www.chess.com/analysis/game/live/142059093930/review. Move 5 you have a free knight for the taking. But you don't take it. Move 13 you hang your bishop. Thankfully your opponent misses it. Move 15 - you sack your bishop for a pawn. The pawn is defended by 3 pieces... for some reason your opponent retook with their queen. Move 20 you block a check with your bishop and blunder it when you should have just stepped your king away. Hopefully this goes to show, if you weren't doing crazy piece sacrificing and were not blunder pieces, and taking your opponents blundered pieces, you would be gaining rating. It's not about tactics at this level, it's about good chess principles, playing really solid, basic chess. Making sure all your pieces have something to do and being ready for when your opponent makes a mistake and does the crazy things you've been doing. Because the crazy stuff is the mistake. So good news, if you stop doing it and instead be solid and let your opponent do it, you will gain a ton of rating points.

Improving Your Chess - Resources for Beginners and Beyond…

https://www.chess.com/blog/RussBell/improving-your-chess-resources-for-beginners-and-beyond