Question Need advice about the game monetization.

I'm working on a simple 3D mobile game. The game itself is just a challenge, where you need to collect more gems than bots (NPCs) for a given period of time. Also, there is an online 1 to 1 mode, where you can challenge anyone online.
As the game is pretty simple, there is no point in selling it for money. So, the game will be free to play, but then i have doubts about the monetization. In the case of ads, they will work only if people will play mostly offline mode, right?
In the case of online, ads make no sense, as no one puts ads for online mode. (Do they?)
Another method is to limit the free version (no online, only a few levels are open), but full access if you unlock the full game.
Not sure which one will work, so, any advice is welcome here.

Thanks in advance.

 

What do you mean by offline?
If user disables network, then no monetisation is available. Also many games turns off adds when offline. This is a way to skip annoying ads.

Again, what do you mean by online here?
Are you mixing erms multiplier and single player?

Do ads or paid. Dont do both, as you will get negative reviews bomb.

Also, try just release game if you haven't before. You need some traction, to get more followers and downloads. See how market behaves. If you do too aggressive monetisation, your system will do more harm than good.

You can add monetisation later.
But also, it may be backslashes by players, who are already playing and suddenly see ads.