I was going to reply, but I just made it a topic,
You can view it here: Ways to earn robux
if your game is popular and is with gamepass that anyone buy then you will get % from this gamepasses to your player or group funds. if premium player play your game you will get also robux for every time he play your game. more way to get robux is sell assets. (if you going put on player screen buy ui every single second the player prob no going to buy the gamepass.)
Patience. Just wait for your game to grow up. Then the big money will come. Trust me.
I deleted this post character limit
If you get users with premium to play your game, you can earn robux depending on the time they spend in your game.
Learn more about it here: Engagement-Based Payouts | Documentation - Roblox Creator Hub
Before you make a game, you should do commissions for people in order to gain funding for said game.
No problem, I know it can be hard to start, but with hard work and consistent effort you can succeed