People say it’s easy to bond babies, because babies generally get on with anyone. But often two baby bunnies that are ‘bonded’ start to fight as soon as they turn into hormonal teenagers. So while it’s easy to put two babies together, it generally doesn’t work in the long term and you end up having to separate them after a fight.
So, the best way to establish a stable bond between the two bunnies is to keep them separated until at least a month after they’re both neutered. Keeping them in cages next door to each other, and swapping them between areas is a good way to get them used to each other’s smells before you start actual bonding. You’re right that a fight between them would make it harder to bond them later, but if you take it slowly and prebond, then you have a good chance of successfully bonding them
I had my two boys living side by side for 2 months before starting to bond them, and they immediately groomed each other and flopped on their first official meeting.