Suppose Alice and Bob are trying to decide who should take out the trash. Naturally, they decide to flip a coin.

However, realizing they no longer have any physical coins to flip, they decide flip their coin onchain.

Where can they get some reliable randomness?

Is this layer 1 eth or perhaps a specific higher level chain

I only hear people talk about chain link vrf but if it's low stakes and maybe time isn't critical you could do some kind of commit reveal depending on what happens as a result or how timely / cheap execution should be?

Let's assume there is no randao, or we don't trust the randao.