Engaging Web-Based Coin Collection Game

I want to develop a simple, web-based, addictive, online game where you collects coins/points

first preferance: a car driving game like https://www.crazygames.com/game/racing-limits

I'm not very particular about the game. It can also be something simple like these where you collect coins/points.

https://yourbrand.city-booster.com/
https://flappybird.io/

Requirements:

1) game needs to be locked. and it should be playable only with a voucher code (generated on my website. So, validation needs to be done)
2) should be playable in a browser - both desktop and mobile
3) game should have a leaderboard option so Top 10 players with max coins win prizes.
4) game challenge level: intermediate. (Not too easy or Not too difficult) - coin placements needs to change with each game so it should not be predicatble
5) Single level is enough - I dont need multiple levels
6) game leaderboard should be shown in another page, which gets updated as people play games.
7) If you already have a similar game, I dont mind using it if it meets my above requirements. I'm still testing my idea, so at this stage, i'm on a budget. so quote accordingly.