First off, let me say that your ads aren’t very appealing. If I saw your ad I would not click on it, let alone play your game. The ads look pretty boring in that it’s just a guy either holding blocks or a gun. You should probably work on making your ads better.
Second, I noticed your game only has 1 thumbnail, and like your ad, it’s very unappealing and boring. All I see is a guy holding blocks and two other people pointing guns at the guy holding the blocks. The thumbnail tells me almost nothing about the game, as the only words it has on it is “RUSH”. You need to put a short teaser on your thumbnails, like “SHOOT YOUR ENEMIES” or something like that.
Third, 500 Robux is NOT enough to get you a sufficient number of players. You need to spend at least a couple thousand (5k - 10k) and that will usually get you around 100-200 concurrent players. Adding on to that, in my point of view you will actually LOSE money from advertising, rather than gain. The reason is because you are only selling loot boxes as your only source of income. That’s pretty bad monetization. You need to make some gamepasses too like a better gun or something like that.
Fourth, where’s the tutorial? Not having a tutorial will just drive away new players since they won’t know how to play. I joined your game just now, and I didn’t have any idea of what to do until I read the description on the Roblox website. You need to script a tutorial to pop up for new players when they join your game. When people click on advertisements, they rarely read the description before clicking “Play”.
Fifth, I don’t want to offend you or anything, but your game is extremely boring in my opinion. I am just running around, getting boxes, and shooting others. What’s the point of the game? The game has very little gameplay features at the moment, you need to add more gameplay features so players will keep coming back to play. Like I said, I just joined, and I don’t feel like playing again, because it is so boring and there is literally nothing to do except run around and shoot people and collecting blocks. If I am missing something, then that leads back to my tutorial suggestion, you need a tutorial so new players can be introduced to everything in your game.
Tl;Dr - Your ads and thumbnail aren’t appealing, and you are not spending enough money on advertising. Your game also lacks a tutorial to help new players get started, leaving most of them clueless of how to play the game. Your game lacks gameplay features and gets quite boring after a few minutes.
Also, like @3rdhoan123 mentioned, why the heck are you kicking people for “high lag”?!? That is absolutely ridiculous and if I were to be kicked for that, I would leave a dislike and never come back, let alone the fact that I have never seen a game kick me for that. Not everybody has super “high tech” devices that can run Roblox games at a good speed. Lag is not something you need to worry about. If high lag plays a major negative role in your game, you need to redesign your game so EVERYBODY can play, including those 20 year old PC users. Everybody should be able to play your game, or you will not get very good results.